The characteristic equation is derived for the LP modes of quadruple-clad fibers. Normalized cutoff frequencies of a few lowest modes are accurately calculated and their universal curves for a variety of structure parameters are presented. It is shown that the cutoff properties of quadruple-clad libers are different from those of singly and doubly elad fibers. The height and thickness of the second cladding shoudn t be too large in order to obtain single mode operation at the interesting wavelength.

The present work ig based upon the teaching materials of experimental holography given by Professor J. Upatnieks used at the Electrical and Computer Engineering Department, Michigan University. After making some improvements in the optical system according the experimental conditions in our institute, we succeeded in taking several holograms of wide angle and great scene of Sozhou garden models (120 visual angle, 260 cm depth and 100 ×250 em area) and obtained a bright and sharp 3-D reconstructed image. Therefore, this technique provides a cheap and practical method for taking holograms of great visual angle and scene in engineering structures, holograpkio display, advertisement, artistic photography, data-storage, etc.

An astigmatic system constructed by inserting a certain amount of astigmatism, a cylindrical concave lens with a large radius of curvature-into a typical one-step rainbow holographic configuration is proposed as orthoscopic configuration to fabricate one-step rainbow holograms. The possibility of obtaining a visual-distortionless reconstructed image by using such system is analysed theoretically. Experiments show that when the rainbow hologram fabricated by such technique is reconstructed for primary image whith a white light point source, a good stereoscopic, quasi-monocliromatic, 3-D orthoscopic image is obtained.

In this paper, the symmetric spheric mirror resonators are analyzed by means of quasi-geometric approximations. The eigenmodes of the resonators are obtained analytically. The periodic properties of the diffraction losses of the unstable resonators with regard to the Fresnel number N are obtained for the first time.

The first tunable Q-switch alexandrite laser in China with high power and giant pulse output is reported in this paper. The tunable range of 730-790nm, linewidth of 0.8nm, pulse width of 30 ns and peak power of 10 MW have been achieved. Using a LiIO3 crystal as frenquency doubler, the SHG tunable range of 368-393nm and power conversion efficiency of 9% have been obtained.

In this paper, coupled-wave equations are solved for large signals by means of numerical integration. A numerical method for calculating SHG and THG efficiencies of beams with Gaussian temporal profiles is given. A high-efficiency frequency tripling seheme for low and moderate power levels is presented. With type-I β-BaB2O4 crystal used in doubling and type-II KD*P used in tripling, energy conversion efficiencies of TEG as high as 41.8% have been achieved at an energy level of 365mJ.

The formulae of second harmonic generation at GaAs-Al interface on a rectangular grating are presented. According to the nonlinear medium theory given by Bloem bergen and Pershan, we have solved Maxwell equations by using pertubution method in power of the surface roughness parameter. All formulae and calculations show that the surface-enhanced second harmonic generation arises from resonant excitation of surface polaritons.

In this paper a quantum mechanics model for describing multiphoton optical bistability is given. Based on this molel, the state equation of multi-photon option1 bistability is obtained. The method which for calculating the threshold of multi-photon optical bistability is also given. After analyzing the potential function, we obtain the statics stability criterion and the explanation of switching characteristics. The stable region and the inferior stable region in the bistability characteristic curve are separated. In fact, multiphoton optical stable states are actually multi-pliotoa optical siable-inferior stable states. AVe nlso discuss the phaso transition problem of multi-photon optical bistability and multi-photon lasers.

Using the DET equations proposed by Feder on microcomputer, we have proved that in evaluating a differential matrix the differential method is better than the difference method. It s advantages include high precision, high computing speed in the case of several variables and good convergence ability in automatic design programs.

In this paper the design of a large angular aperture acousto-optic tunable filter (AOTF) using TeO2 crystals is described. A new crystal orientation with θα= 100° and θi, =23.4° is proposed. It has been proved in the experiments that this AOTF meets Hi e exact condition of tangent momentum match. The measured tuning relation is in good agreement with theoretical calculations and the spectral resolution has been improved by nearly 10A. After compensation, the change in deflection angle is decreased to ±0.06°.

A compact optical switch has been constructed, which consists of two pieces of Cr-GaAs, a resistor and a KD*P crystal, and is controlled by mode-locked optical pulses. The open time of the switch is oontinuosuly variable from sub-nsec to several tens of nsec, and its responsive time is as short as 280 pseo.

Infrared reflection spectra at room temperature have been investigated for TGS-family ferroelectric crystals, including TGS. DTGS and ATGSP. The observed lines are tabled and classified according to their wavenumber and modes. We have found that there is a line at 930cm-1 resnlting from PO43--ions group on the infrared spectra of ATGSP. This indicates that the phosphoric acid enters the crystal, replacing sulphuric acid.

The 5snd and 5snd Rydberg series of Sr were selectively excited from the 5s2 1So ground state by using two pulsed tunable dye lasers pumped by the harmonic of a Nd: YAG laser. Afterwards, the Rydberg atoms were photo-ionized by a third laser pulse. The energy levels and quantum defects have been measured for more than seventy Rydberg states of Sr.

The application of a holographic leng in optical information processing with speckle encoding is presented. The hololens used is made under optimum condition. As an example, experimental results of multi-image storage with speckle encoding using the hololens is given.

Reported here is an experimental investigation of the three-step photoionization of U atoms using a hollow cathode discharge (HOD) tube as both the atom source and photoionization signal detector.

Raman spectra of LiZnTa3O9 crystal have been obtained for the first time and compared with those of LiTaO3. Rorward-Baman scattering shows that there is no polariton dispersion in LiZnTa3O9, thus we can conclude that the symmetry of LiZnTa3O9 crystal is D34 point group. Finally, Raman spectra of LiZnTa3O9 are assigned and discussed.

A CW tunable dye laser was used to measure the optogalvanic spectroseopv of Eu. Sixth five spectral lines were observed, among them 61 are irom EuI, and 4 are from EuII.