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Laser-induced breakdown spectroscopy (LIBS) is a type of atomic emission spectroscopy which uses a highly energetic laser pulse as the excitation source.[1][2] The laser is focused to form a plasma, which atomizes and excites samples. The formation of the plasma only begins when the focused laser achieves a certain threshold for optical breakdown, which generally depends on the environment and the target material.[3] In principle, LIBS can analyze any matter regardless of its physical state, be it solid, liquid or gas. Because all elements emit light of characteristic frequencies when excited to sufficiently high temperatures, LIBS can (in principle) detect all elements, limited only by the power of the laser as well as the sensitivity and wavelength range of the spectrograph & detector. If the constituents of a material to be analyzed are known, LIBS may be used to evaluate the relative abundance of each constituent element, or to monitor the presence of impurities. In practice, detection limits are a function of a) the plasma excitation temperature, b) the light collection window, and c) the line strength of the viewed transition. LIBS makes use of optical emission spectrometry and is to this extent very similar to arc/spark emission spectroscopy.

LIBS operates by focusing the laser onto a small area at the surface of the specimen; when the laser is discharged it ablates a very small amount of material, in the range of nanograms to picograms, which generates a plasma plume with temperatures in excess of 100,000 K. During data collection, typically after local thermodynamic equilibrium is established, plasma temperatures range from 5,000 to 20,000 K. At the high temperatures during the early plasma, the ablated material dissociates (breaks down) into excited ionic and atomic species. During this time, the plasma emits a continuum of radiation which does not contain any useful information about the species present, but within a very small timeframe the plasma expands at supersonic velocities and cools. At this point the characteristic atomic emission lines of the elements can be observed. The delay between the emission of continuum radiation and characteristic radiation is in the order of 10 μs, which is why it is necessary to temporally gate the detector.

LIBS is sometimes referred to as laser-induced plasma spectroscopy (LIPS); however that acronym also has alternative meanings that are outside the field of analytical spectroscopy.

LIBS is technically very similar to a number of other laser-based analytical techniques, sharing much of the same hardware. These techniques are the vibrational spectroscopic technique of Raman spectroscopy, and the fluorescence spectroscopic technique of laser-induced fluorescence (LIF). In fact devices are now being manufactured which combine these techniques in a single instrument, allowing the atomic, molecular and structural characterisation of a specimen as well as giving a deeper insight into physical properties.

Design

A typical LIBS system consists of a Nd:YAG solid-state laser and a spectrometer with a wide spectral range and a high sensitivity, fast response rate, time gated detector. This is coupled to a computer which can rapidly process and interpret the acquired data. As such LIBS is one of the most experimentally simple spectroscopic analytical techniques, making it one of the cheapest to purchase and to operate.

The Nd:YAG laser generates energy in the near infrared region of the electromagnetic spectrum, with a wavelength of 1064 nm. The pulse duration is in the region of 10 ns generating a power density which can exceed 1 GW·cm−2 at the focal point. Other lasers have been used for LIBS, mainly the Excimer (Excited dimer) type that generates energy in the visible and ultraviolet regions.

The spectrometer consists of either a monochromator (scanning) or a polychromator (non-scanning) and a photomultiplier or CCD detector respectively. The most common monochromator is the Czerny–Turner type whilst the most common polychromator is the Echelle type. However, even the Czerny-Turner type can be (and is often) used to disperse the radiation onto a CCD effectively making it a polychromator. The polychromator spectrometer is the type most commonly used in LIBS as it allows simultaneous acquisition of the entire wavelength range of interest.

The spectrometer collects electromagnetic radiation over the widest wavelength range possible, maximising the number of emission lines detected for each particular element. Spectrometer response is typically from 1100 nm (near infrared) to 170 nm (deep ultraviolet), the approximate response range of a CCD detector. All elements have emission lines within this wavelength range. The energy resolution of the spectrometer can also affect the quality of the LIBS measurement, since high resolution systems can separate spectral emission lines in close juxtaposition, reducing interference and increasing selectivity. This feature is particularly important in specimens which have a complex matrix, containing a large number of different elements. Accompanying the spectrometer and detector is a delay generator which accurately gates the detector's response time, allowing temporal resolution of the spectrum.
Advantages

Because such a small amount of material is consumed during the LIBS process the technique is considered essentially non-destructive or minimally-destructive, and with an average power density of less than one watt radiated onto the specimen there is almost no specimen heating surrounding the ablation site. Due to the nature of this technique sample preparation is typically minimised to homogenisation or is often unnecessary where heterogeneity is to be investigated or where a specimen is known to be sufficiently homogeneous, this reduces the possibility of contamination during chemical preparation steps. One of the major advantages of the LIBS technique is its ability to depth profile a specimen by repeatedly discharging the laser in the same position, effectively going deeper into the specimen with each shot. This can also be applied to the removal of surface contamination, where the laser is discharged a number of times prior to the analysing shot. LIBS is also a very rapid technique giving results within seconds, making it particularly useful for high volume analyses or on-line industrial monitoring.

LIBS is an entirely optical technique, therefore it requires only optical access to the specimen. This is of major significance as fiber optics can be employed for remote analyses. And being an optical technique it is non-invasive, non-contact and can even be used as a stand-off analytical technique when coupled to appropriate telescopic apparatus. These attributes have significance for use in areas from hazardous environments to space exploration. Additionally LIBS systems can easily be coupled to an optical microscope for micro-sampling adding a new dimension of analytical flexibility.

With specialised optics or a mechanically positioned specimen stage the laser can be scanned over the surface of the specimen allowing spatially resolved chemical analysis and the creation of 'elemental maps'. This is very significant as chemical imaging is becoming more important in all branches of science and technology.

Portable LIBS systems are more sensitive, faster and can detect a wider range of elements (particularly the light elements) than competing techniques such as portable x-ray fluorescence. And LIBS does not use ionizing radiation to excite the sample, which is both penetrating and potentially carcinogenic.
Disadvantages

LIBS, like all other analytical techniques is not without limitations. It is subject to variation in the laser spark and resultant plasma which often limits reproducibility. The accuracy of LIBS measurements is typically better than 10% and precision is often better than 5%. The detection limits for LIBS vary from one element to the next depending on the specimen type and the experimental apparatus used. Even so, detection limits of 1 to 30 ppm by mass are not uncommon, but can range from >100 ppm to <1 ppm.
2000s developments

From 2000 to 2010, the U.S. Army Research Laboratory (ARL) researched potential extensions to LIBS technology, which focused on hazardous material detection.[4][5] Applications investigated at ARL included the standoff detection of explosive residues and other hazardous materials, plastic landmine discrimination, and material characterization of various metal alloys and polymers. Results presented by ARL suggest that LIBS may be able to discriminate between energetic and non-energetic materials.[6]
Research

In 2000, ARL and Ocean Optics Inc. developed a broadband high-resolution spectrometer which was commercialized in 2003. Designed for material analysis, the spectrometer allowed the LIBS system to be sensitive to chemical elements in low concentration.[7]

ARL LIBS applications studied from 2000 to 2010 included:[5]

Tested for detection of Halon alternative agents
Tested a field-portable LIBS system for the detection of lead in soil and paint
Studied the spectral emission of aluminum and aluminum oxides from bulk aluminum in different bath gases
Performed kinetic modeling of LIBS plumes
Demonstrated the detection and discrimination of geological materials, plastic landmines, explosives, and chemical and biological warfare agent surrogates

ARL LIBS prototypes studied during this period included:[5]

Laboratory LIBS setup
Commercial LIBS system by Ocean Optics, Inc.
Man-portable LIBS device
Standoff LIBS system developed for 100+ m detection and discriminate on of explosive residues.

2010s developments

In the 2010s, interest developed in LIBS that focused on the miniaturization of the components and the development of compact, low-power, portable systems. Interest from groups such as NASA and ESA - as well as the military - has furthered these developments. The Mars Science Laboratory mission brought ChemCam, a LIBS instrument, to the surface of Mars in 2012.

Recent developments in LIBS have seen the introduction of double-pulsed laser systems.[8][9] For double-pulse LIBS one distinguishes between orthogonal and perpendicular configuration. In perpendicular configuration the laser fires twice on the same spot on the specimen with a pulse separation in the order of one to a couple of tens of microseconds. Depending on pulse separation, the second pulse is more or less absorbed by the plasma plume caused by the previous pulse, resulting in a reheating of the laser plasma leading to signal enhancement. In orthogonal configuration a laser pulse is fired parallel to the sample surface either before or after the perpendicular pulse hits the specimen. The laser plasma ignited in the surrounding medium above the surface by a first pulse causes (by its shock wave) an area of reduced pressure above the specimen into which the actual plasma from the sample can expand. This has similar positive effects on sensitivity like LIBS performed at reduced pressures. If the orthogonal laser pulse is delayed with respect to the perpendicular one, the effects are similar as in the perpendicular configuration. Timing electronics such as digital delay generators can precisely control the timing of both pulses.

Both double-pulse LIBS as well as LIBS at reduced pressures aim at increasing the sensitivity of LIBS and the reduction of errors caused by the differential volatility of elements (e.g. hydrogen as an impurity in solids). It also significantly reduces the matrix effects. Double-pulsed systems have proven useful in conducting analysis in liquids, as the initial laser pulse forms a cavity bubble in which the second pulse acts on the evaporated material.

LIBS is one of several analytical techniques that can be deployed in the field as opposed to pure laboratory techniques e.g. spark OES. As of 2015, recent research on LIBS focuses on compact and (man-)portable systems. Some industrial applications of LIBS include the detection of material mix-ups,[10] analysis of inclusions in steel, analysis of slags in secondary metallurgy,[11] analysis of combustion processes,[12] and high-speed identification of scrap pieces for material-specific recycling tasks. Armed with data analysis techniques, this technique is being extended to pharmaceutical samples.[13][14]
LIBS using short laser pulses

Following multiphoton or tunnel ionization the electron is being accelerated by inverse Bremsstrahlung and can collide with the nearby molecules and generate new electrons through collisions. If the pulse duration is long, the newly ionized electrons can be accelerated and eventually avalanche or cascade ionization follows. Once the density of the electrons reaches a critical value, breakdown occurs and high density plasma is created which has no memory of the laser pulse. So, the criterion for the shortness of a pulse in dense media is as follows: A pulse interacting with a dense matter is considered to be short if during the interaction the threshold for the avalanche ionization is not reached. At the first glance this definition may appear to be too limiting. Fortunately, due to the delicately balanced behavior of the pulses in dense media, the threshold cannot be reached easily. The phenomenon responsible for the balance is the intensity clamping[15] through the onset of filamentation process during the propagation of strong laser pulses in dense media.

A potentially important development to LIBS involves the use of a short laser pulse as a spectroscopic source.[16] In this method, a plasma column is created as a result of focusing ultrafast laser pulses in a gas. The self-luminous plasma is far superior in terms of low level of continuum and also smaller line broadening. This is attributed to the lower density of the plasma in the case of short laser pulses due to the defocusing effects which limits the intensity of the pulse in the interaction region and thus prevents further multiphoton/tunnel ionization of the gas.[17][18]
Line intensity

For an optically thin plasma composed of a single, neutral atomic species in local thermal equilibrium (LTE), the density of photons emitted by a transition from level i to level j is[19]

\( {\displaystyle I_{ij}(\lambda )={\frac {1}{4\pi }}n_{0}A_{ij}{\frac {g_{i}\exp ^{-E_{i}/k_{B}T}}{U(T)}}I(\lambda )} \)

where :

\( I_{{ij}} \) is the emission rate density of photons (in m−3 sr−1 s−1)
\( n_{0} \) is the number of neutral atoms in the plasma (in m−3)
\( A_{ij} \) is the transition probability between level i and level j (in s−1)
\( g_{i} \) is the degeneracy of the upper level i (2J+1)
\( {\displaystyle U(T)} \) is the partition function (in s−1)
\( E_{i} is the energy level of the upper level i (in eV)
\( k_{B} \) is the Boltzmann constant (in eV/K)
T is the temperature (in K)
\( I(\lambda) \) is the line profile such that \( {\displaystyle \int _{-\infty }^{\infty }I(\lambda )d\lambda =1} \)
\( \lambda \) is the wavelength (in nm)

The partition function \({\displaystyle U(T)} \) is the statistical occupation fraction of every level k {\displaystyle k} k of the atomic species :

\( {\displaystyle U(T)=\sum _{j}g_{j}\exp ^{-E_{j}/k_{B}T}} \)

LIBS for food analysis

Recently, LIBS has been investigated as a fast, micro-destructive food analysis tool. It is considered a potential analytical tool for qualitative and quantitative chemical analysis, making it suitable as a PAT (Process Analytical Technology) or portable tool. Milk, bakery products, tea, vegetable oils, water, cereals, flour, potatoes, palm date and different types of meat have been analyzed using LIBS.[20] Few studies have shown its potential as an adulteration detection tool for certain foods.[21][22] LIBS has also been evaluated as a promising elemental imaging technique in meat.[23]

In 2019, researchers of the University of York and of the Liverpool John Moores University employed LIBS for studying 12 European oysters (Ostrea edulis, Linnaeus, 1758) from the Late Mesolithic shell midden at Conors Island (Republic of Ireland). The results highlighted the applicability of LIBS to determine prehistoric seasonality practices as well as biological age and growth at an improved rate and reduced cost than was previously achievable.[24]
See also

Spectroscopy
Atomic spectroscopy
Raman spectroscopy
Laser-induced fluorescence
List of plasma (physics) articles
List of surface analysis methods
Laser ablation
Photoacoustic spectroscopy

References

Radziemski, Leon J.; Cremers, David A. (2006). Handbook of laser-induced breakdown spectroscopy. New York: John Wiley. ISBN 0-470-09299-8.
Schechter, Israel; Miziolek, Andrzej W.; Vincenzo Palleschi (2006). Laser-induced breakdown spectroscopy (LIBS): fundamentals and applications. Cambridge, UK: Cambridge University Press. ISBN 0-521-85274-9.
J. P. Singh and S. N. Thakur, Laser-Induced Breakdown Spectroscopy, 1st ed.. (Elsevier, 2007).
Munson, Jennifer L. Gottfried Frank C. De Lucia Jr. Andrzej W. Miziolek Chase A. "Current Status of Standoff LIBS Security Applications at the United States Army Research Laboratory". www.spectroscopyonline.com. Retrieved 2018-08-27.
Gottfried, Jennifer L.; De Lucia, Frank C., Jr. (2010). "Laser-Induced Breakdown Spectroscopy: Capabilities and Applications". doi:10.21236/ada528756.
"Detection of Energetic Materials and Explosive Residues With Laser-Induced Breakdown Spectroscopy: I. Laboratory Measurements" (PDF).
"U.S. Army Researchers Explore Laser Detection Techniques | Quality Digest". www.qualitydigest.com. Retrieved 2018-08-27.
Ahmed, Rizwan; Baig, M. Aslam (2009). "A comparative study of single and double pulse laser induced breakdown spectroscopy". Journal of Applied Physics. 106 (3): 033307–033307–6. Bibcode:2009JAP...106c3307A. doi:10.1063/1.3190516. ISSN 0021-8979.
Ahmed, R; Baig, M A (2010). "On the Optimization for Enhanced Dual-Pulse Laser-Induced Breakdown Spectroscopy". IEEE Transactions on Plasma Science. 38 (8): 2052–2055. Bibcode:2010ITPS...38.2052A. doi:10.1109/TPS.2010.2050784. ISSN 0093-3813. S2CID 42072463.
Noll, Reinhard; Bette, Holger; Brysch, Adriane; Kraushaar, Marc; Mönch, Ingo; Peter, Laszlo; Sturm, Volker (2001). "Laser-induced breakdown spectrometry — applications for production control and quality assurance in the steel industry". Spectrochimica Acta Part B: Atomic Spectroscopy. 56 (6): 637–649. Bibcode:2001AcSpe..56..637N. doi:10.1016/s0584-8547(01)00214-2.
Sanghapi, Hervé K.; Ayyalasomayajula, Krishna K.; Yueh, Fang Y.; Singh, Jagdish P.; McIntyre, Dustin L.; Jain, Jinesh C.; Nakano, Jinichiro (2016). "Analysis of slags using laser-induced breakdown spectroscopy". Spectrochimica Acta Part B: Atomic Spectroscopy. 115: 40–45. Bibcode:2016AcSpe.115...40S. doi:10.1016/j.sab.2015.10.009.
Hsu, Paul S.; Gragston, Mark; Wu, Yue; Zhang, Zhili; Patnaik, Anil K.; Kiefer, Johannes; Roy, Sukesh; Gord, James R. (2016). "Sensitivity, stability, and precision of quantitative Ns-LIBS-based fuel-air-ratio measurements for methane-air flames at 1–11 bar". Applied Optics. 55 (28): 8042–8048. Bibcode:2016ApOpt..55.8042H. doi:10.1364/ao.55.008042. PMID 27828047.
St-Onge, L.; Kwong, E.; Sabsabi, M.; Vadas, E.B (2002). "Quantitative analysis of pharmaceutical products by laser-induced breakdown spectroscopy". Spectrochimica Acta Part B: Atomic Spectroscopy. 57 (7): 1131–1140. Bibcode:2002AcSpe..57.1131S. doi:10.1016/s0584-8547(02)00062-9.
Myakalwar, Ashwin Kumar; Sreedhar, S.; Barman, Ishan; Dingari, Narahara Chari; Venugopal Rao, S.; Prem Kiran, P.; Tewari, Surya P.; Manoj Kumar, G. (2011). "Laser-induced breakdown spectroscopy-based investigation and classification of pharmaceutical tablets using multivariate chemometric analysis". Talanta. 87: 53–59. doi:10.1016/j.talanta.2011.09.040. PMC 3418677. PMID 22099648.
Xu, Shengqi; Sun, Xiaodong; Zeng, Bin; Chu, Wei; Zhao, Jiayu; Liu, Weiwei; Cheng, Ya; Xu, Zhizhan; Chin, See Leang (2012). "Simple method of measuring laser peak intensity inside femtosecond laser filament in air". Optics Express. 20 (1): 299–307. Bibcode:2012OExpr..20..299X. doi:10.1364/oe.20.000299. PMID 22274353.
A. Talebpour et al., Spectroscopy of the Gases Interactingwith Intense Femtosecond Laser Pulses, 2001, Laser Physics, 11:68–76
Talebpour, A.; Abdel-Fattah, M.; Chin, S.L (2000). "Focusing limits of intense ultrafast laser pulses in a high pressure gas: Road to new spectroscopic source". Optics Communications. 183 (5–6): 479–484. Bibcode:2000OptCo.183..479T. doi:10.1016/s0030-4018(00)00903-2.
Geints, Yu. E.; Zemlyanov, A. A. (2009). "On the focusing limit of high-power femtosecond laser pulse propagation in air". The European Physical Journal D. 55 (3): 745–754. Bibcode:2009EPJD...55..745G. doi:10.1140/epjd/e2009-00260-0. S2CID 121616255.
Reinhard., Noll (2012). Laser-induced breakdown spectroscopy : fundamentals and applications. Springer-Verlag Berlin Heidelberg. ISBN 9783642206672. OCLC 773812336.
Markiewicz-Keszycka, Maria; et al. (2017). "Laser-induced breakdown spectroscopy (LIBS) for food analysis: A review". Trends in Food Science & Technology. 65: 80–93. doi:10.1016/j.tifs.2017.05.005.
Sezer, Banu; et al. (2018). "Identification of milk fraud using laser-induced breakdown spectroscopy (LIBS)". International Dairy Journal. 81: 1–7. doi:10.1016/j.idairyj.2017.12.005.
Dixit, Yash; et al. (2017). "Laser induced breakdown spectroscopy for quantification of sodium and potassium in minced beef: a potential technique for detecting beef kidney adulteration". Analytical Methods. 9 (22): 3314–3322. doi:10.1039/C7AY00757D.
Dixit, Yash; et al. (2018). "Introduction to laser induced breakdown spectroscopy imaging in food: Salt diffusion in meat". Journal of Food Engineering. 216: 120–124. doi:10.1016/j.jfoodeng.2017.08.010.

Hausmann, Niklas; Robson, Harry K.; Hunt, Chris (2019-09-30). "Annual Growth Patterns and Interspecimen Variability in Mg/Ca Records of Archaeological Ostrea edulis (European Oyster) from the Late Mesolithic Site of Conors Island". Open Quaternary. 5 (1): 9. doi:10.5334/oq.59. ISSN 2055-298X.

Lee, Won-Bae; Wu, Jianyong; Lee, Yong-Ill; Sneddon, Joseph (2004). "Recent Applications of Laser-Induced Breakdown Spectrometry: A Review of Material Approaches". Applied Spectroscopy Reviews. 39 (1): 27–97. Bibcode:2004ApSRv..39...27L. doi:10.1081/ASR-120028868. ISSN 0570-4928. S2CID 98545359.
Noll, Reinhard; Bette, Holger; Brysch, Adriane; Kraushaar, Marc; Mönch, Ingo; Peter, Laszlo; Sturm, Volker (2001). "Laser-induced breakdown spectrometry — applications for production control and quality assurance in the steel industry". Spectrochimica Acta Part B: Atomic Spectroscopy. 56 (6): 637–649. Bibcode:2001AcSpe..56..637N. doi:10.1016/S0584-8547(01)00214-2. ISSN 0584-8547.

Further reading

Andrzej W. Miziolek; Vincenzo Palleschi; Israel Schechter (2006). Laser Induced Breakdown Spectroscopy. New York: Cambridge University Press. ISBN 0-521-85274-9.
Gornushkin, I.B.; Amponsah-Manager, K.; Smith, B.W.; Omenetto, N.; Winefordner, J.D. (2004). "Microchip Laser Induced Breakdown Spectroscopy: Preliminary Feasibility Investigation". Applied Spectroscopy. 58 (7): 762–769. Bibcode:2004ApSpe..58..762G. doi:10.1366/0003702041389427. PMID 15282039. S2CID 41416641. Archived from the original on 2013-04-15.
Amponsah-Manager, K.; Omenetto, N.; Smith, B. W.; Gornushkin, I. B.; Winefordner, J. D. (2005). "Microchip laser ablation of metals: Investigation of the ablation process in view of its application to laser-induced breakdown spectroscopy". Journal of Analytical Atomic Spectrometry. 20 (6): 544. doi:10.1039/B419109A.
Lopez-Moreno, C.; Amponsah-Manager, K.; Smith, B. W.; Gornushkin, I. B.; Omenetto, N.; Palanco, S.; Laserna, J. J.; Winefordner, J. D. (2005). "Quantitative analysis of low-alloy steel by microchip laser induced breakdown spectroscopy". Journal of Analytical Atomic Spectrometry. 20 (6): 552. doi:10.1039/B419173K. S2CID 39938942.
Bette, H; Noll, R (2004). "High speed laser-induced breakdown spectrometry for scanning microanalysis". Journal of Physics D: Applied Physics. 37 (8): 1281. Bibcode:2004JPhD...37.1281B. doi:10.1088/0022-3727/37/8/018.
Balzer, Herbert; Hoehne, Manuela; Noll, Reinhard; Sturm, Volker (2006). "New approach to online monitoring of the Al depth profile of the hot-dip galvanised sheet steel using LIBS". Analytical and Bioanalytical Chemistry. 385 (2): 225–33. doi:10.1007/s00216-006-0347-z. PMID 16570144. S2CID 42607960.
Sturm, V.; Peter, L.; Noll, R. (2000). "Steel analysis with laser-induced breakdown spectrometry in the vacuum ultraviolet". Applied Spectroscopy. 54 (9): 1275–1278. Bibcode:2000ApSpe..54.1275S. doi:10.1366/0003702001951183. S2CID 32765892.
Vadillo, José M.; Laserna, J.Javier (2004). "Laser-induced plasma spectrometry: Truly a surface analytical tool". Spectrochimica Acta Part B: Atomic Spectroscopy. 59 (2): 147. Bibcode:2004AcSpe..59..147V. doi:10.1016/j.sab.2003.11.006.
Doucet, François R.; Faustino, Patrick J.; Sabsabi, Mohamad; Lyon, Robbe C. (2008). "Quantitative molecular analysis with molecular bands emission using laser-induced breakdown spectroscopy and chemometrics". Journal of Analytical Atomic Spectrometry. 23 (5): 694. doi:10.1039/b714219f.
В.Копачевский, В.Шпектор, Д.Клемято, В.Бойков, М.Кривошеева, Л.Боброва. (2008). "Количественный анализ состава тарных стекол анализатором LEA S500". Фотоника (in Russian) (1): 38–40.
Noll, Reinhard (2012). Laser-Induced Breakdown Spectroscopy: Fundamentals and Applications. Berlin: Springer. ISBN 978-3-642-20667-2.

External links

NIST LIBS Database

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Spectroscopy
Vibrational

FT-IR Raman Resonance Raman Rotational Rotational–vibrational Vibrational Vibrational circular dichroism

UV–Vis–NIR

Ultraviolet–visible Fluorescence Vibronic Near-infrared Resonance-enhanced multiphoton ionization (REMPI) Raman optical activity spectroscopy Raman spectroscopy Laser-induced

X-ray and
photoelectron

Energy-dispersive X-ray spectroscopy Photoelectron Atomic Emission X-ray photoelectron spectroscopy EXAFS

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Gamma Mössbauer

Radiowave

NMR Terahertz ESR/EPR Ferromagnetic resonance

Others

Acoustic resonance spectroscopy Auger spectroscopy Astronomical spectroscopy Cavity ring-down spectroscopy Circular dichroism spectroscopy Coherent anti-Stokes Raman spectroscopy Cold vapour atomic fluorescence spectroscopy Conversion electron Mössbauer spectroscopy Correlation spectroscopy Deep-level transient spectroscopy Dual-polarization interferometry Electron phenomenological spectroscopy EPR spectroscopy Force spectroscopy Fourier-transform spectroscopy Glow-discharge optical emission spectroscopy Hadron spectroscopy Hyperspectral imaging Inelastic electron tunneling spectroscopy Inelastic neutron scattering Laser-induced breakdown spectroscopy Mössbauer spectroscopy Neutron spin echo Photoacoustic spectroscopy Photoemission spectroscopy Photothermal spectroscopy Pump–probe spectroscopy Saturated spectroscopy Scanning tunneling spectroscopy Spectrophotometry Time-resolved spectroscopy Time-stretch Thermal infrared spectroscopy Video spectroscopy Vibrational spectroscopy of linear molecules

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Lasers

List of laser articles List of laser types List of laser applications Laser acronyms

Laser types: Solid-state
Semiconductor Dye Gas
Chemical Excimer Ion Metal Vapor

Laser physics

Active laser medium Amplified spontaneous emission Continuous wave Doppler cooling Laser ablation Laser cooling Laser linewidth Lasing threshold Magneto-optical trap Optical tweezers Population inversion Resolved sideband cooling Ultrashort pulse

Laser optics

Beam expander Beam homogenizer B Integral Chirped pulse amplification Gain-switching Gaussian beam Injection seeder Laser beam profiler M squared Mode-locking Multiple-prism grating laser oscillator Multiphoton intrapulse interference phase scan Optical amplifier Optical cavity Optical isolator Output coupler Q-switching Regenerative amplification

Laser spectroscopy

Cavity ring-down spectroscopy Confocal laser scanning microscopy Laser-based angle-resolved photoemission spectroscopy Laser diffraction analysis Laser-induced breakdown spectroscopy Laser-induced fluorescence Noise-immune cavity-enhanced optical heterodyne molecular spectroscopy Raman spectroscopy Second-harmonic imaging microscopy Terahertz time-domain spectroscopy Tunable diode laser absorption spectroscopy Two-photon excitation microscopy Ultrafast laser spectroscopy

Laser ionization

Above-threshold ionization Atmospheric-pressure laser ionization Matrix-assisted laser desorption/ionization Resonance-enhanced multiphoton ionization Soft laser desorption Surface-assisted laser desorption/ionization Surface-enhanced laser desorption/ionization

Laser fabrication

Laser beam welding Laser bonding Laser converting Laser cutting Laser cutting bridge Laser drilling Laser engraving Laser-hybrid welding Laser peening Multiphoton lithography Pulsed laser deposition Selective laser melting Selective laser sintering

Laser medicine

Computed tomography laser mammography Laser capture microdissection Laser hair removal Laser lithotripsy Laser coagulation Laser surgery Laser thermal keratoplasty LASIK Low-level laser therapy Optical coherence tomography Photorefractive keratectomy Photorejuvenation

Laser fusion

Argus laser Cyclops laser GEKKO XII HiPER ISKRA lasers Janus laser Laboratory for Laser Energetics Laser integration line Laser Mégajoule Long path laser LULI2000 Mercury laser National Ignition Facility Nike laser Nova (laser) Novette laser Shiva laser Trident laser Vulcan laser

Civil applications

3D laser scanner CD DVD Blu-ray Laser lighting display Laser pointer Laser printer Laser tag

Military applications

Advanced Tactical Laser Boeing Laser Avenger Dazzler (weapon) Electrolaser Laser designator Laser guidance Laser-guided bomb Laser guns Laser rangefinder Laser warning receiver Laser weapon LLM01 Multiple Integrated Laser Engagement System Tactical High Energy Laser Tactical light ZEUS-HLONS (HMMWV Laser Ordnance Neutralization System)

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