Methods based on the Stark effect are reviewed for dither-free frequency stabilization of the opticallypumped submm laser. The CO₂ pump laser was stabilized using either the linear absorption or the nonlinear Lamb dip of the submm lasant in an external Stark cell. Estimated frequency stability (Δf/f) of the order of 10^-8-10^-9, over a period of one hour, was obtained by these methods for several CO₂laser lines. The frequencyof the submm laser was stabilized using the d.c. and a.c. Stark effects for a metal-dielectric rectangular waveguide laser. An estimated frequency stability of ±6×10^-8 was obtained, for example, for 119, μmline of CH₃OH laser for one hour recording.

View full abstract

The mass-productive duplication technology for holographic grating using the embossing method was developed.The rainbow hologramd uplication technology using this embossing method was established. And thehologram transfer foil was developed in response to demands for making holograms to printed matters. Theseholograms are used for various printing products and premiump roducts as well as for security purpose. In thispaper, these technology are explained. Futhermore, the applications and the future trend are discussed.

View full abstract

A computer-controlled system of laser microirradiation is developed for photobiological study. The system determines irradiation positions and manipulates laser beams automatically.
We present here the computational procedure of image processing and the method of laser manipulationas well as their experimental results.
The procedure time needed for cell-microirradiation is extremely reduced as compared with the manualoperation of the laser microirradiation system. The average irradiation time of O .3s/cell is obtained experimentally, including the computer processing time.

View full abstract

Deposition of hydrogenated carbon films by photodissociation of aromatic hydrocarbons using Ar F or Kr F excimer laser beam directed parallel to a substrate has been demonstrated. Infrared absorption spectrum and transmission election diffraction pattern show that the films mainly contain diamond like structure and partially contain graphite like structure. Optical bandgap of the films calculated by using ultraviolet spectrum sows that the hydrogen content of the films is different when the laser wavelength, the materials or the substrate temperature is different.

View full abstract

The design and construction of a differential absorption lidar (DIAL) system for measuring NO₂ in the urban atmosphere are described. Two-wavelength laser beams in the blue region generated by a dye laser pumped by a Nd: YAG laser are used as the light source for the DIAL measurement. The wavelengths are switched alternately with the pulse repitition rate of 10 pps. The minimum detectabie NO₂ concentration (signal-to-noiseratio=5) for the DIAL system is 10 ppb for a 10-minute measurement.

View full abstract