Abstract: A surface plasmon sensor comprises a prism, a metal film, which is formed on one surface of the prism and is brought into contact with a sample, and a light source for producing a light beam. An optical system causes the light beam to pass through the prism and to impinge upon an interface between the prism and the metal film such that various different angles of incidence may be obtained with respect to the interface. A photodetector detects an intensity of the light beam, which has been totally reflected from the interface, with respect to each of the various different angles of incidence. An electrode stands facing the metal film with a liquid sample intervening therebetween, and a DC voltage is applied across the electrode and the metal film. A substance contained in the liquid sample is thus analyzed quickly and with a high sensitivity.

Abstract: A surface plasmon sensor includes a prism, a metal film which is formed on one face of the prism and is brought into contact with a sample, a light source emitting a light beam, and an optical system which causes the light beam to enter the prism so that various angles of incidence of the light beam to the interface between the prism and the metal film can be obtained. First and second photodetectors respectively detect the amounts of light of first and second parts of the light beam reflected in total reflection from the interface. The first part is a light bundle reflected from the interface at angles in a first reflecting angle range and the second part is a light bundle reflected from the interface at angles in a second reflecting angle range different from the first reflecting angle range. A comparator compares the light amount signal output from the first photodetector with that output from the second photodetector.

Abstract: A surface plasmon sensor comprises a prism, a metal film, which is formed on one surface of the prism and is brought into contact with a sample, and a light source for producing a light beam. An optical system causes the light beam to pass through the prism and to impinge upon an interface between the prism and the metal film such that various different angles of incidence may be obtained with respect to the interface. A photodetector detects an intensity of the light beam, which has been totally reflected from the interface, with respect to each of the various different angles of incidence. An electrode stands facing the metal film with a liquid sample intervening therebetween, and a DC voltage is applied across the electrode and the metal film. A substance contained in the liquid sample is thus analyzed quickly and with a high sensitivity.

Abstract: An optical wavelength converting apparatus comprises a semiconductor laser, which is capable of oscillating in a multiple longitudinal mode, and an external resonator for resonating a laser beam, which has been radiated out of the semiconductor laser and which serves as a fundamental wave. An optical wavelength converting device is located in an optical path of the fundamental wave, which has been resonated by the external resonator. A device feeds part of the fundamental wave, which has been resonated by the external resonator, back to the semiconductor laser. A wavelength-converted wave in a single longitudinal mode is thereby obtained, which wave has a high intensity and is stable.

Abstract: A non-linear optical effect frequency conversion laser of the present invention which can stabilize the oscillation frequency thereof, and which can convert the frequency of laser light emitted by a laser light source using a ring resonator composed of a non-linear optical element comprises a thermoelectric conversion device provided for the laser light source to maintain a predetermined temperature thereof, a temperature sensor also provided for the laser light source to measure the temperature thereof, a comparator for comparing a detection signal in response to the temperature of the laser light source outputted from the temperature sensor with a reference voltage signal in response to a predetermined temperature, and a driver means in response to the differential voltage signal outputted from the comparator for driving the thermoelectric conversion device as a cooling device for the purpose of stabilizing the oscillation of the laser light source.

Abstract: There is disclosed an optical frequency converter of a bulk resonator structure comprising a ring resonator or V-shaped resonator made of a nonlinear optical crystal. The converter is equipped with a means for returning a laser light emitted by a semiconductor laser resonating inside the resonator to the semiconductor laser. The ring resonator or V-shaped resonator is made small in size and compact. The converter is insusceptible to vibration and needs no adjustment. Returning laser light is produced at less locations. The loss of the output light inside the resonator is reduced. The second harmonic is generated at a high efficiency. Multiple reflection is produced inside the resonator to further enhance the efficiency of the generation of the second harmonic of the laser radiation. Also, the phase of the radiation can be made uniform. The optical density can be increased.