Abstract: An information carrier medium includes at least first and second sheet members (12, 14) each having first and second surfaces opposite to each other and laminated together with the first surface of the first sheet member bonded to the first surface of the second sheet member. A security indicium (14; 71) is formed on at least one of the first surfaces of the respective first and second sheet members (12, 14). The security indicium is made of at least one inking material of a kind capable of responding to a coherent light when irradiated thereby. An electro-optical reader for reading the security indicium (14; 71) is also disclosed.

Abstract: An image measuring apparatus for measuring an image of a tooth or gum applies the radiation of a laser beam to permit extremely quick, reliable, safe detection of dental caries and other dental pathological conditions. The low incident power of the laser radiation would not cause damage or pain to the tissue, such as the tooth or gum. The image measuring apparatus is equipped with a light source which emits light having at least a wavelength in a range of 500 nm or more to less than 600 nm; it uses the light emitted from the light source to obtain 2-dimensional images or computed tomographic images of a tooth or gum from the light, which has been transmitted through the tooth or gum, by using an optical heterodyne detection method.

Abstract: A microscopic specimen such as a cell organelle or a tissue cell generally has a non-rotational symmetrical refractive index distribution. Converging onto the microscopic specimen a laser beam with a non-rotational symmetrical intensity distribution (an elliptical pattern) traps the specimen, with the direction of the major axis of the specimen aligned with the direction of the major axis of the elliptical pattern of the laser beam. This is because the laser beam with the non-rotational symmetrical refractive index distribution has a non-rotational symmetrical trapping force, and hence can trap the specimen with non-rotational symmetrical refractive index distribution in a dynamically reliable manner. Thus, rotation of the major axis of the intensity distribution of the laser beam causes rotation of the trapped specimen.

Abstract: A junction-type semiconductor light emitting device comprising a plate portion, a column formed on one surface of the plate portion and electrodes provided on each of opposite surfaces of the plate portion including the column wall, the column having a pn junction formed therein and extending perpendicular to the plate portion, the plate portion having a pn junction formed therein and extending in parallel with the plate portion, these pn junctions being connected with each other, the current density through the pn junction in the column being larger than that through the pn junction in the plate portion under the application of a predetermined voltage across the electrodes, so as to facilitate the continuous oscillation of this light emitting device at room temperature with the resultant light emission through the column. The light emitting device can be readily arranged in matrix and readily integrated in high degree.

Abstract: An optical function semiconductor device formed by opto-electrical loop coupling of a light emitting diode and a photodetector, the latter of which receives a part of an output light of the former controlled by an output current thereof, can be readily miniaturized and integrated as a fundamental function active device self-containing a light source and presenting various useful novel functions of the optoelectronic technology between the external input and the output lights.

Abstract: A laser functional device formed by photoelectric direct loop coupling of a laser diode and a photodetector, the latter of which receives a part of an output light of the former together with an external input light and excites the former by an output current thereof, can be easily miniaturized and integrated as a fundamental function active device self-containing a light source and presenting various useful functions of the optoelectronic technology between the external input and the output lights.