An infrared detection system comprises the following elements. A laser source provides radiation for illuminating a target (5). This radiation is tuned to at least one wavelength in the fingerprint region of the infrared spectrum. A detector (32) detects radiation backscattered from the target (5). An analyser determines from at least the presence or absence of detected signal in said at least one wavelength whether a predetermined volatile compound is present. An associated detection method is also provided. In embodiments, the laser source is tunable over a plurality of wavelengths, and the detector comprises a hyperspectral imaging system. The laser source may be an optical parametric device has a laser gain medium for generating a pump beam in a pump laser cavity, a pump laser source and a nonlinear medium comprising a ZnGeP.sub.2 (ZGP) crystal. On stimulation by the pump beam, the ZnGeP.sub.2 (ZGP) crystal is adapted to generate a signal beam having a wavelength in a fingerprint region of the spectrum and an idler beam having a wavelength in the mid-infrared region of the spectrum. The laser gain medium and the ZnGeP.sub.2 (ZGP) crystal are located in the pump wave cavity.

A class of erbium-doped silicate crystals have a general chemical formula of (Er.sub.xYb.sub.yCe.sub.zA.sub.(1-x-y-z)).sub.3RM.sub.3Si.sub.2O.sub.14, in which the range of x is 0.002 to 0.02, y is 0.005 to 0.1, and z is 0 to 0.15; A is one, two or three elements selected from Ca, Sr, or Ba; R is one or two elements selected from Nb or Ta; M is one or two elements selected from Al or Ga. Using one of such crystals as a gain medium and a diode laser at 940 nm or 980 nm as a pumping source, a 1.5 m continuous-wave solid-state laser with high output power and high efficiency, as well as a pulse solid-state laser with high energy and narrow width can be obtained.

A class of erbium-doped silicate crystals have a general chemical formula of (Er.sub.xYb.sub.yCe.sub.zA.sub.(1-x-y-z)).sub.3RM.sub.3Si.sub.2O.sub.14, in which the range of x is 0.002 to 0.02, y is 0.005 to 0.1, and z is 0 to 0.15; A is one, two or three elements selected from Ca, Sr, or Ba; R is one or two elements selected from Nb or Ta; M is one or two elements selected from Al or Ga. Using one of such crystals as a gain medium and a diode laser at 940 nm or 980 nm as a pumping source, a 1.5 m continuous-wave solid-state laser with high output power and high efficiency, as well as a pulse solid-state laser with high energy and narrow width can be obtained.

A laser transmitter assembly for use in a Coherent Doppler Wind Lidar (CDWL) system includes a telescope/scanner assembly, a receiver, and a master oscillator crystal and a power amplifier crystal each constructed of Ho:YAG. The crystals are end-pumped to transmit an output beam through the telescope/scanner assembly with a high repetition rate of 200-300 Hz and 35 mJ of energy. As part of the CDWL system, a pump laser end-pumps the master oscillator and power amplifier crystals using a pump beam having a nominal wavelength of 1.905 m. A seed laser transmits a seeding beam into the master oscillator crystal at a nominal wavelength of 2.0965 m. The telescope/scanner assembly transmits the generated laser beam through an atmosphere toward a scene of interest, collects a backscattered return signal, and communicates the backscattered return signal to the receiver during operation of the CDWL system.

A laser transmitter assembly for use in a Coherent Doppler Wind Lidar (CDWL) system includes a telescope/scanner assembly, a receiver, and a master oscillator crystal and a power amplifier crystal each constructed of Ho:YAG. The crystals are end-pumped to transmit an output beam through the telescope/scanner assembly with a high repetition rate of 200-300 Hz and 35 mJ of energy. As part of the CDWL system, a pump laser end-pumps the master oscillator and power amplifier crystals using a pump beam having a nominal wavelength of 1.905 m. A seed laser transmits a seeding beam into the master oscillator crystal at a nominal wavelength of 2.0965 m. The telescope/scanner assembly transmits the generated laser beam through an atmosphere toward a scene of interest, collects a backscattered return signal, and communicates the backscattered return signal to the receiver during operation of the CDWL system.

A laser device includes a light source device including a semiconductor laser; and a laser cavity irradiated with light from the light source device and including a saturable absorber. A beam waist diameter r of the light that irradiates the laser cavity and an initial transmittance T.sub.0 of the saturable absorber satisfy a relationship of 7.75T.sub.0.sup.47.77T.sub.0.sup.3+3.13T.sub.0.sup.2+0.16T.sub.0+0.74r2.62T.sub.0+0.675.

A laser device includes a light source device including a semiconductor laser; and a laser cavity irradiated with light from the light source device and including a saturable absorber. A beam waist diameter r of the light that irradiates the laser cavity and an initial transmittance T.sub.0 of the saturable absorber satisfy a relationship of 7.75T.sub.0.sup.47.77T.sub.0.sup.3+3.13T.sub.0.sup.2+0.16T.sub.0+0.74r2.62T.sub.0+0.675.

The present disclosure discloses a double trigger type single pulse laser apparatus configured to suppress additional pulses to increase single pulse energy and improve stability of output as compared to a conventional single trigger type single pulse laser apparatus. According to the present invention, there is provided a single pulse laser apparatus including a resonator which has a first mirror, a second mirror, a gain medium, an electro-optic modulator and an acousto-optic modulator configured to respectively perform Q-switching and mode-locking, the single pulse laser apparatus including a first photodiode configured to measure a laser beam oscillated by the resonator.

The present disclosure discloses a double trigger type single pulse laser apparatus configured to suppress additional pulses to increase single pulse energy and improve stability of output as compared to a conventional single trigger type single pulse laser apparatus. According to the present invention, there is provided a single pulse laser apparatus including a resonator which has a first mirror, a second mirror, a gain medium, an electro-optic modulator and an acousto-optic modulator configured to respectively perform Q-switching and mode-locking, the single pulse laser apparatus including a first photodiode configured to measure a laser beam oscillated by the resonator.

Disclosed is a laser apparatus including a laser generator comprising a laser medium, a pumping light source providing light to the laser medium, a first mirror and a second mirror arranged with the laser medium therebetween, and configured to generate a laser beam of a first wavelength, a secondary harmonic wave generator configured to generate a laser beam of a second wavelength from the laser beam of a first wavelength, a light modulator arranged between the laser medium and the secondary harmonic wave generator and configured to adjust a pulse width of the laser beam of a first wavelength, and an output adjustor configured to adjust an output of the laser beam of a second wavelength generated in the secondary harmonic wave generator.