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A new calibration method for infrared hyperspectral imaging Fourier transform spectrometer is presented. Two kinds of common materials as Polypropylene (PP) and Polyethylene Terephthalate (PET) films which have special absorption peaks in the infrared band were used in the calibration experiment. As the wavelengths at the sharp absorption peaks of the films are known, an infrared imaging spectrometer can be calibrated on spectra with two or three peaks. With high precision and stability, this method simplifies the calibration work. It is especially appropriate for the measuring condition with a lack of calibration equipment or with inconvenience to calibrate the multiple light sources outdoors.

This paper reported the algorithm for Infrared Hyperspectral Imaging Radiometric Spectrometer Technology. Six different apodization functions are been used and compared, and the phase corrected technologies of Forman is researched and improved, fast fourier transform(FFT)is been used in this paper instead of the linear convolution to reduce the quantity of computation.The interferograms is achieved by the Infrared Hyperspectral Imaging Radiometric Spectrometer which are corrected and rebuilded by the improved algorithm, this algorithm reduce the noise and accelerate the computing speed with the higher accuracy of spectrometers.

We report the research results on Solid-State Laser System for Terahertz Radiation Generation. Terahertz radiation generation is based on a double longitudinal mode laser with a single linear cavity and laser amplifiers. The laser is LD pumped CW Nd:YVO4 laser with a single linear cavity. The double longitudinal mode laser beam makes it very convenient to control their propagation for Terahertz radiation generation. The relative intensities of the modes and the frequency difference between the modes can be adjusted for high efficiency generating THz radiation with required frequency. The CW laser beam was first amplified by a LD end-pumped Nd:YVO4 amplifier, then it was changed into pulsed beam by an LN electro-optical modulator. The pulsed laser beam was amplified by other four Nd:YVO4 amplifiers pumped by three 6W LDs and a 35W optical fiber coupled LDA, respectively，and became strong enough and was projected into an organic nonlinear optical crystal DAST to generate THz radiation with narrow linewidth and stable frequency. By this method a new kind of THz wave source can be developed. It is smaller in size, high efficient and no any adjustment is needed in applications. The paper reports the experimental setup and results in details.

The Computed-Tomography Imaging Interferometer (CTII) is a novel imaging spectrometer, which combines the advantages of the conventional Fourier Transform Imaging Spectrometer (FTIS) and the ordinary Computed-Tomography Imaging Spectrometer (CTIS). CTII obtains multi-angle projection interferograms by rotating Dove prism placed in the collimating light beams. The image reconstruction is carried out by using computed-tomography reconstruction algorithm named Radon transform. However, in experiments, images reconstructed from the raw projection-interferogram sequences, are badly distorted. To solve this problem, we find when Dove prism is rotated, its rotation center is not coincident to the optic axis of CTII. Therefore, the raw projection-interferogram sequences have a few deviations to the ideal sequences. And then we find the deviations follow certain law, so it is possible to rectify the raw projection-interferogram sequences. In this paper, two methods, the Linear rectification method and the Cosine rectification method are proposed. The Linear rectification method uses an image processing method, gets the dither value at each rotation angle, and rectifies the raw images. The Cosine rectification method supposes the dither follows cosine change; the detail is presented in this paper. Finally, the reconstruction images are presented. The reconstruction results show these two rectification methods are feasible and effective.

This paper presents a novel imaging spectrometer, the Computed-Tomography Imaging Interferometer (CTII). CTII is the combination of the conventional Fourier Transformation Imaging Spectrometer (FTIS) and the Computed-Tomography Imaging Spectrometer (CTIS).This system consists of a telescope system, a collimating system, a Dove prism, a cylindrical lens, a Michelson interferometer, and a focal plane array sensor. Therefore, CTII retains the advantages of both FTIS and CTIS such as high etendue, high spectral resolution and the snapshot ability. In this paper, the basic principle of CTII is introduced. And the experimental system of a CTII is constructed. The experimental results show CTII is feasible.

By combining the techniques of AO (acousto-optic) Q-switching and EO (electro-optic) cavity-dumping, a new type of diode-pumped nanosecond pulsed laser was proposed for the first time. The Q- switched pulses at 1.06micrometers with a peak power of 5.02kW and a pulse width 3.1ns pumped a 1W laser diode on the Nd:YVO 4 microchip at the 1kHz repetition rate were obtained. The temporal characteristics of the pulses were analyzed numerically. The experiment results are shown to be in good agreement with theoretical predictions.

The electro-optic characteristics of the KTP crystal are analyzed in detail and Q-switched operation of a diode-laser- pumped Nd:YVO4 laser is reported using an intracavity KTP crystal. The KTP crystal was used as both an electro-optic Q- switcher and a frequency-doubling crystal in type II phase matching for generating pulsed green beams. Compared with the conventional frequency-doubling and Q-switching configuration where a Q-switcher and a frequency-doubling crystal was needed, low loss and high efficiency characteristics were realized by only using KTP crystal in our experimental setup. With the new type of KTP crystal doped particular element, the great green pulsed output was obtained continuously for a long time with no sign of electrochromic damage. In this paper, we demonstrated a relatively new and compact intracavity frequency-doubled and Q-switched Nd:YVO4 laser. The short- cavity laser was longitudinally pumped with a diode laser.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A QCW 100W LD array side pumped high power laser has been developed. The 1.O6m laser pulseenergy of 2mJ, with the pulse width 20 ns and repetition frequency 7OHz5KHz is obtained. Using thenon-cylinder lens focus system developed by our group, the efficient conversion of pump energy into 106pm TEM00 mode is achieved with 17% optical-optical efficiency. The effect of vibrating outputcoupler in the laser resonator strengths the output power has been found for the first time.Keywords: LD array, side pump, focus system, vibrationINTRODUCTION Progress in the development of high-power diode laser (LD) and diode laser arrays (LDA) hasrenewed interest in LD pumped solid-state laser, especially in the high average power with high repetition frequency up to 1KHz area. Conventional LD end pumping rod laser has the advantage of highlight-light conversion efficiency, low threshold and high beam quality. Although these devices arecompact and efficient, they don't scale well to large size and high pump power. Furthermore, underoperating conditions the thermally loaded rod laser gain medium exhibits optical distortions includingthermal focusing, stress induced biaxial focusing and stress induced birefringence, which severelydegrade the optical quality of the laser beam and eventually limit the laser output power. The slab laserwith the zig-zag path is an solution to these thermal effect.Through theoretical study of the slab laser, in idea case, the slab laser can eliminate stress inducedbirefringence by slab geometry and thermal and stress induced focusing by optical propagation along azigzag path. The only power limit is the stress induced fracture of the laser medium. So the slab laser hasplay more and more important role in the high power solid state laser area.

We report here LD pumped Q-Switched LNYAB Self-frequency-doubling Laser. Under 570mW of O.8O2.tm pumping power, the series pulses of O.53j.im green laser with 4.2ns of pulse width and 750W of peak power have been measured . The laser reliably operates when Q—switching rate ranges from CW to 100kHz. The highest peak power was obtained at repetition rate of 10kHz. To our knowledge, it is the first LD pumped acoustooptic Q-switched LNYAB green laser in the world and should be a desirable and reliable pulsed green laser source in the future. KEY WORDS: Self-frequency-doubling Laser, LD Pumped, LNYAB, Q-Switched

We report here the Nd:YAP-KTP red laser pumped by LD for pumping Cr:LiSAF tunable laser. Using a CW 802 nm LD of 3 W, 670 nm CW red laser of 95 mW has been measured. The red laser is used to pump Cr:LiSAF laser, and over 4 mW CW laser from the Cr:LiSAF laser has been measured. They are to our knowledge the first Nd:YAP-KTP red laser pumped by LD and the first Cr:LiSAF laser pumped by Nd:YAP-KTP red laser.

Here we report LD pumped solidified miniature Nd:YAG laser and Nd: YVO4 laser with KTPcrystal as intracavity frequency doubling material. Using 1W LD 70 mW and 80 mW of the green laser output in TEMOO mode have been measured for Nd:YAG laser and Nd:YVO4 laser, respectively. The output stability is better than and the beam quality coefficient M2 is smallerthan 1.2. The laser is small in size and very suitable for optical recording and storage.KEYWORDS: miniature CW green laser, LD pumped, optical recording and storage ' 1. INTRODUCTION Now the Information age has come. Optical recording and storage become very important for societydeveloping. Laser diode (LD) are broadly used in Optical recording and storage field. But wavelength of theinfrared LD used in the field is still relatively longer, and is a limit to raise the storage density. Blue- green lasers have much shorter wavelengths. They can be focused into a much smaller spot and enhance the storage density several times. Many efforts have been made to develop blue-green LDs. But up to now no