Statistics for Spatial Data.

Switches, and Actuators Masahiro Irie,*,† Tuyoshi Fukaminato,‡ Kenji Matsuda, and Seiya Kobatake †Research Center for Smart Molecules, Rikkyo University, Nishi-Ikebukuro 3-34-1, Toshima-ku, Tokyo 171-8501, Japan ‡Research Institute for Electronic Science, Hokkaido University, N20, W10, Kita-ku, Sapporo 001-0020, Japan Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan Department of Applied Chemistry, Graduate School of Engineering, Osaka City University, Sugimoto 3-3-138, Sumiyoshi-ku, Osaka 558-8585, Japan

Photochromism of Diarylethene Molecules and Crystals: Memories, Switches, and Actuators

Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

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Light-emitting diodes

Introduction to Mathematical Statistics. By R.V. Hogg and A. T. Craig. Pp. ix, 245. 47s. 1959. (The Macmillan Company, New York)

Manufacturing and measurement of freeform optics

A micro displacement sensor and its sensing technique based on line-defect resonant cavity in photonic crystals (PhCs) are presented. The line-defect resonant cavity is formed by a fixed and a mobile PhC segments. With a proper operating frequency, a quasi-linear measurement of micro-displacement is achieved with sensitivity of 1.15 a(-1) ( a is the lattice constant) and Q factor of 40. The sensitivity can be adjusted easily by varying either Q factor or operating frequency of the sensing system. In addition, the sensing range can be broadened to -0.55 a ~0.60 a by using multiple operating frequencies. The properties of the micro displacement sensor are analyzed theoretically and simulated using finite-difference time-domain (FDTD) method.

Micro displacement sensor based on line-defect resonant cavity in photonic crystal.

Conventional double random phase encoding (DRPE) encrypts plaintext to white noise-like ciphertext which may attract attention of eavesdroppers, and recent research reported that DRPE is vulnerable to various attacks. Here we propose a security enhanced optical encryption system that can hide the existence of secret information by watermarking. The plaintext is encrypted using iterative fractional Fourier transform with random phase key, and ciphertext is randomly permuted with permutation key before watermarking. Cryptanalysis shows that linearity of the security system has been broken and the permutation key prevent the attacker from accessing the ciphertext in various attacks. A series of simulations have shown the effectiveness of this system and the security strength is enhanced for invisibility, nonlinearity and resistance against attacks.

Security enhanced optical encryption system by random phase key and permutation key

A new diarylethene doped with poly(methyl methacrylate) film is developed and its characteristics of volume holographic recording are investigated. The maximum diffraction efficiency of the 10microm thick film is 1.2%, and the rewritable hologram recording exhibits its high resolution, fatigue resistance, negligible shrinkage, and long lifetime, which are critical to apply this material to high-density rewritable holographic data storage.

Photochromic diarylethene for rewritable holographic data storage

Astigmatism is left uncorrected in traditional Czerny-Turner spectrometers with spherical mirrors, which leads to low throughput of modern instruments applying line-array detectors. By gradually varying the sagittal curvature, freeform mirrors are introduced to suppress astigmatism for a wide wavelength range simultaneously. So as not to reduce spectrum resolution, further calculations of the light path are performed for extra coma compensation. A design example is presented with optimized parameters. The ray-tracing result has revealed a reduction in sagittal spot size from several hundred micrometers to around 10 microm in the wavelength range from 200 nm to 800 nm.

Qingsheng He

Papers

Micro displacement sensor based on line-defect resonant cavity in photonic crystal.

Security enhanced optical encryption system by random phase key and permutation key

Photochromic diarylethene for rewritable holographic data storage

Design of freeform mirrors in Czerny-Turner spectrometers to suppress astigmatism

Enhancement of the light output of light-emitting diode with double photonic crystals