Development of an efficient coherent optical source at 6.04μm (original) (raw)
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Third harmonic generation of CO 2 laser radiation in AgGaSe 2 crystal
2000
Generation of third harmonic of CO¾ laser radiation has been obtained in a type-II, AE cut 9 mm thick AgGaSe¾ crystal for the first time by sum-frequency-mixing of the fundamental with its second harmonic, the latter being obtained using another type-I, AE cut 11 mm thick AgGaSe¾ crystal. The energy conversion efficiencies obtained for second harmonic and third harmonic generations are 6.3% and 2.4% respectively with the input fundamental pump power density of 5.9 MW/cm ¾ only. The wavelength of the fundamental CO¾ laser radiation used for the generation of harmonics is 10.6 m, È (20) line. A compact TEA CO¾ laser source has been built in the laboratory.
Efficiency as high as 26% is obtained for generation of mid-infrared radiation at 6.04 lm by frequency doubling of ammonia laser emission at 12.08 lm in a 15 mm long type-I cut AgGaSe 2 crystal. The NH 3 laser used for this work is optically pumped by a commercial TEA CO 2 laser operating on 9.22 lm and produces pulsed output of 210mJwithadurationof210 mJ with a duration of 210mJwithadurationof200 ns at 12.08 lm. The generated radiation at 6.04 lm is separated out from the residual radiation at 12.08 lm by exploiting the principle of polarization dependent diffraction of reflection grating.
Optics Express, 2006
We report a study of the effect of optical absorption on generation of coherent infrared radiation from mid-IR to THz region from GaSe crystal. The infrared-active modes of ε-GaSe crystal at 236 cm-1 and 214 cm-1 were found to be responsible for the observed optical dispersion and infrared absorption edge. Based upon phase matching characteristics of GaSe for difference-frequency generation (DFG), new Sellmeier equations of GaSe were proposed. The output THz power variation with wavelength can be properly explained with a decrease of parametric gain and the spectral profile of absorption coefficient of GaSe. The adverse effect of infrared absorption on (DFG) process can partially be compensated by doping GaSe crystal with erbium ions.
Applied Optics, 1993
The availability of new nonlinear optical materials such as AgGaS 2 and AgGaSe 2 and improvements in compact, tunable, pulsed and continuous-wave (cw) solid-state pump lasers now make it possible to generate tunable, infrared narrow-band coherent radiation over a wide wavelength range (4-18 ,um) by means of difference-frequency generation (DFG). This article describes the wavelength and outputpower characteristics of a tunable infrared source based on AgGaSe 2 and certain proven cw near-infrared pump sources for application to high-resolution spectroscopy.
Difference-frequency generation in AgGaS_2 by use of single-mode diode-laser pump sources
Optics Letters, 1993
We explored the suitability of visible III-V single-mode cw diodes for difference-frequency generation of tunable infrared radiation by mixing a red single-mode cw III-V diode laser with a tunable single-frequency cw Ti:sapphire laser in AgGaS 2. More than 1 ILW of cw tunable, infrared (A 5 ,um), narrow-band coherent radiation was generated with type I noncritical phase matching. The wavelength and output-power characteristics of this novel tunable all-solid-state laser source are described, and we demonstrate the applicability of the source to high-resolution molecular spectroscopy by obtaining a test spectrum. The feasibility of a more compact solidstate cw laser spectrometer based on the mixing of two single-mode diode lasers (808 and 690 nm) as pump sources in AgGaS 2 is shown (infrared power generated-3 nW).
Tangentially phase-matched infrared detection in AgGaS 2
Journal of Physics D: Applied Physics, 1994
Detection of infrared radiation (10 p n) by a nonlinear up-conversion technique under a tangential phase-matched situation in AgGaS2 crystal with Nd:YAG laser as a pump has been demonstrated. A wide angular tolerance has also been obtained with a view to achieving mechanical stability. Its capability of detecting a low-level infrared signal at room temperature and its temperature-dependency have also been demonstrated. Non-critical (Koidl and Jantz 1979) and near non-critical
Infrared Lasers in Nanoscale Science
CO2 Laser - Optimisation and Application, 2012
The N 2 laser is known as a pulse ultraviolet laser and in addition it covers some lines in the infrared up to 8,2 µm. Normally, the pulse width is a few nanoseconds and a high-voltage power supply of 30-40 kV is necessary to excite it. The HF is a high power chemical laser media with an emission wavelength of about 2,7 µm, a laser pulse of the order of µs in duration and the output energy ranges from 1 J to more than 1 kJ per pulse. The DF and HBr chemical lasers emit larger wavelengths than the HF laser, and their output power is lower [1,2]. www.intechopen.com CO 2 Laser-Optimisation and Application 326 The CO 2 laser is a gas laser electrically pumped, that emits in the mid-infrared. It gives a cw output at 10 µm in the infrared with a high efficiency and it is the most practical molecular laser. There are a large number of CO 2 lasers, varying in structure, method of excitation and capacity, which can provide hundreds of laser lines, the main ones being between 9 and 11 µm. The output power of even a small CO 2 laser is about 1 kW and large ones give over 10 kW. The usual way of obtaining single-line oscillation is to use a diffraction grating in conjunction with a laser resonator. If only mirrors are used, simultaneous oscillation on several lines in the neighborhood of 10,6 µm is commonly obtained [1,2]. Transverse excited atmosphere (TEA) CO 2 lasers have a very high (about atmospheric) gas pressure. As the voltage required for a longitudinal discharge would be too high, transverse excitation is done with a series of electrodes along the tube. TEA lasers are operated in pulsed mode only, as the gas discharge would not be stable at high pressures, and are suitable for average powers of tens of kilowatts [1,2]. Although N 2 O and CO laser have a lower output power than the CO 2 laser, they have about one hundred laser lines each in the ranges 10-11 µm and 5-6,5 µm, respectivelly (considering the main isotopic species). The molecules NH 3 , OCS, CS also have quite a few laser lines in the infrared. With the SO 2 , HCN, H 2 O, many laser lines are obtained in the infrared from 30 µm up to submilimeter wavelengths [1,2]. Dye lasers are convenient tunable lasers in the visible but not so far in the infrared, mainly due to the lack of appropriate dyes, and in addition, since the dye laser medium is liquid, it is very inconvenient to handle.
Mid-Infrared Photon-Pair Generation in AgGaS_2
2021
We demonstrate non-degenerate photon-pair generation by spontaneous parametric down conversion in a silver gallium sulfide AgGaS_2 crystal. By tuning the pump wavelength, we achieve phase matching over a large spectral range. This allows to generate idler photons in the mid-infrared spectral range above 6 μ m wavelength with corresponding signal photons in the visible. Also, we show photon pair generation with broad spectral bandwidth. These results are a valuable step towards the development of quantum imaging and sensing techniques in the mid-infrared.
SECOND OPTICAL HARMONIC GENERATION OF CO 2 LASER RADIATION IN CGA CRYSTAL
J. of Nonlinear Optical Physics & Materials, 2013
In this work, second harmonic generation has been investigated for radiation in IR-range of spectrum at the constant-intensity approximation. The detailed analysis of nonlinear interaction of optical waves have been studied in CGA, ZAP and AgGa 0.6 In 0.4 Se 2 crystals and the comparison of the obtained results have been made on conversion efficiency with experimentally calculated values. The conditions for realization have been determined for the regime close to the uncritical angular phase matching. The recommendations are suggested on elaboration of the reliability of highly efficient generators for second harmonic in the IR-range, specially the generators of second harmonic of the CO 2 lasers.