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Infrared detection possesses a significantly application prospect in the field of astrophysics. Due to the special natures of deep-space exploring objects, the performance of infrared detector is very demanding. Blocked-impurity-band (BIB) infrared detectors, with advantages of wide spectrum coverage, low noise, high sensitivity, good resistance to cosmic particle radiation etc., have become the state-of-the-art choice for astronomical application internationally. The response of BIB detectors ranges from mid-infrared to far-infrared waveband, and the widespread use of BIB detectors help human beings obtain a series of important scientific achievements in the field of deep-space exploration. The research on BIB infrared detector in China started rather late. Even though big progress has been achieved in recent years, it still lags far behind the advanced level globally. This article reviews the research progress for BIB infrared detectors of China in the past 5 years. The preparation technology, physical property characterization, photoelectric response characteristics of BIB infrared detection material and corresponding devices, and the control of surface plasmon polaritons on the photoelectric response of the detectors are introduced detailly. These provide references and experimental bases for the development of BIB infrared detector in China.

In this paper, a hybrid optical-digital system, consisting of a holographic mask, two Fourier lenses, a CCD detector and a microcomputer, is presented for computing a superposition integral, which is expressed as the integral of input data and impulse response or point-spread -function. In principle, the system can be used for performing an arbitrary linear transform and multiplication of matrices, as well as extracting the features of a pattern. In this system all the spacings between the input, lens, mask and output planes are equal to the focal length of the Fourier lens, The point-spread function is represented by the process of lightwave propagating through the optical system and modulating in the mask. The mask is produced by using computer-generated-hologram techniques. In experimental research, the system is tested by Walsh-Hadamard transform, matrix multiplication and geometric moment integral. The experimental results show that, the measured values of the above integrals are in agreement with the theoretical calculations.

A novel kind of optical fibre ring cavity, which acts as 'optical capacitor', is presented. As incident light energy can be stored in this kind of cavity, the beam intensity in it may be increased to a value which is much higher than the input intensity. Some applications are also proposed, such as enhancing the efficiency of nonlinear optical conversions, reducing the drive voltage for electro-optic switches or modulators, increasing the energy utilization ratio for optical switches or modulators and so on.

Fixing of a holographic grating in a single BaTiO(3) crystal is studied in detail by means of a thermal process. Above T = 78 °C, oscillations of the diffracted intensity of the sample appear, which are related to the fixing process. Different methods to perform and optimize the fixing process are described. A fixed diffraction efficiency of ~25% was obtained. Self-enhanced as well as self-depleted diffraction from the fixed photorefractive gratings was observed.

Upon the combination of double refraction and diffraction effects, a new kind of polarization device is proposed, which is made of the birefringent plate with the grooves of a sawtooth profile on its surface. This device may separate an incident light beam into two polarized beams spatially with a high extinction ratio and large beam‐splitting angle, moreover it has a sheet form, large aperture, and low cost, thus being suitable for practical use.

A polarizer which works upon the combination effect of birefringence and diffraction has been designed and realized experimentally. According to the design the polarizer may be consisting of a sheet of birefringent material or two birefringence plates, on which surface one dimensional grooves with a sawtooth profile or echelon profile are carved. In experiment, a periodic grooves of a sawtooth profile were fabricated on the surface of calcite plate by mechanical and optical manufacture techniques. This sample polarizer was test for its polarized feature with a non-polarized HeNe laser, and the results show the polarizer is of a good polarized performance.

We designed and fabricated a diffractive element for high-power laser beam shaping whose output is less sensitive to variations of input intensity and phase distributions. The choice of the initial solution is used as a degree of freedom to conduct the iterations to converge to a suboptimal solution that has the required property. We determined the initial phase by an aperture subdivision and stationary phase method, which is less sensitive to input variations. Experimental results are shown.

In this paper, combining refractive and diffractive effects, a new kind of infrared lenses with wavelength 10.6 mu m was designed and produced for CO2 laser material processing. This refractive-diffractive lens (RDL) converts a CO2 laser beam into the rectangular shape with light intensity distribution in the concave shape at x-direction. A method which employs input aperture division and geometrical transformation technique for obtaining a better initial phase distribution of the iteration is presented. The experimental results show that the desired shape of the output light beam was obtained with a high efficiency in energy utilization.

In this paper, a kind of diffractive optical element (DOE) was designed and fabricated. For the design, an improved Gerchberg-Saxton algorithm and an approach of aperture division are presented. The DOE was generated by means of photolithogrpahy and ion etching techniques with 16 phase levels. The experimental results of quenching processing of steel parts by inserting the DOE into CO2 laser beam are satisfactory. The DOE is of an advantage of that applicable to a variety of multimode laser beams.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Observe and study that the device PROM exhibits an optical isodeusity behavior, which may cause some interest in image processing.PROM is a device constructing with photorefractive crystal BSO (Bai2SiO2o), which is usually used to convert an optical image from incoherent to coherent. Recently, more attention has been devoted to developing applications of PROM in the fields of optical holography, optical informationprocessing and optical computing. In this paper, an optical isodensity behavior ofthe PROM device is observed and measured. Under considerations of the optical nonlinearity of BSO, a relation oftransmission light intensity I with the voltage V within BSO crystal is written by IIosin2(), (1) where Vh S the halfwave voltage of the BSO. As V = Vh, I reaches maximum value Io. It maybe seen that I trends to minimum in the vicinity of zero voltage. The voltage V is sum of appliedexternal voltage V and inner voltage V1 in BSO, whkh is induced by writing exposure E on to BSO. Therefore, by turning V onto —V1 value, a minimum transmission occurs, which corresponds

An adjacent sequence iteration method for designing a dif- fractive element with function of controlling wavefront propagation is pre- sented, and a binary optical element for focusing a diode laser beam in a long focal depth is designed with this method, fabricated by means of photolithography and ion-etching techniques. The simulation calculated with the designed element indicates that the design is successful, and the experiment results of long focal depth by testing the produced ele- ment are consistent with the design requirements. © 2004 Society of Photo

A multilevel binary phase grating polarization device that uses a birefringent material as the substrate is proposed, and the design is described. Based on the effect of combining double refraction with diffraction, this type of device can act as a polarizing beam splitter and has a number of advantages for practical use.

We report a highly efficient self-pumped phase conjugation (SPPC) at near-infrared wavelengths with an undoped BaTiO3. A 80% SPPC reflectivity at 741 nm was achieved. We made a detailed investigation on the buildup process of the phase-conjugate signal. A possible mechanism for this highly efficient SPPC mirror is also discussed.

For improved underwater visibility a method that uses a special intervallic series of light pulses and two acts of emitting and receiving is performed by two specially designed optical shutters and by control signals that are synchronously delayed. Calculations show that the apparent contrast of the target can be improved, and thus the distance over which it is visible can be increased. This method has several advantages that can make it practical for actual use, and its feasibility is demonstrated in experiments.

A 4f-type optical system for performing matrix multiplication is presented. The system consists of a holographic mask and two Fourier lenses. With this system, the inner products of 4 x 8 and 8 x 4 matrices are calculated, yielding results that are in agreement with theoretical values.