Abstract: A magnetic optical element having a Faraday rotator and a polarizer provided integrally on the light transmitting surface of the Faraday rotator; the magnetic optical element being characterized by being constituted of i) a Faraday rotator on each side of which an anti-reflection film has been formed and ii) a polarizer comprising photonic crystals which has been formed on one anti-reflection film. Then, in this magnetic optical element, insofar as no substrate for the polarizer is present, the whole magnetic optical element integrally made up of the Faraday rotator and the photonic-crystal polarizer can be made small in thickness, and hence, when cut into small chips, the chips can not easily scatter, also having the effect of enabling production of inexpensive optical isolators.

Abstract: A non-destructive taste characteristics measuring apparatus comprising trays and a measuring section provided in the course of a transport path and at which light is made incident on a vegetable or fruit to measure its taste characteristics, wherein the trays are each provided with at least two tray-side light passages one opening ends of which are so made as to come in contact with the vegetable or fruit and the other ends of which stand open outward at the bottom of the tray, and the measuring section has at least two measurement-side light passages one opening ends of which are positionally adjustable to the opening ends of the tray-side light passages at its part facing the bottom of said tray, and is provided with i) a means for making light incident on the vegetable or fruit through one of the measurement-side light passages and one of the tray-side light passages and ii) a detector which the light emergent from the vegetable or fruit enters through the other tray-side light passage and the other measur

Abstract: A non-destructive sugar content measuring apparatus for determining the sugar content of a vegetable or fruit by measuring absorption of light in sugar when near infrared light is made incident on the vegetable or fruit; comprising at least one light source that emits light rays having three kinds of wavelengths within a wavelength range of from 860 nm to 960 nm, and a detector that detects the absorption of light.

Abstract: Disclosed is a process for preparing a single crystal of potassium titanium arsenate by flux growth method, wherein a compound of K.sub.2 ZO.sub.4, in which Z is at least one of W, S, Mo and Cr, is used as a flux and the flux is blended with potassium titanium arsenate in such a way that the proportion of potassium titanium arsenate is from 15 to 50 mol % of the whole. The process may be carried out by conventional flux growth method under an atmospheric pressure and gives a single crystal of potassium titanium arsenate at a low cost.