Patent ID: 7826696

Claim:
An optical deflection method comprising: emitting control light and signal light into a light absorption layer in a thermal lens forming optical element so that the control light and the signal light converge at different convergence points in the light absorption layer, wherein a wavelength of the control light is different from a wavelength of the signal light, the wavelength of the control light is selected from a wavelength band that the light absorption layer can absorb, and the wavelength of the signal light is selected from a wavelength band that the light absorption layer cannot absorb; and causing convergence and divergence of the control light and the signal light on an incidence plane of the light absorption layer or its vicinity in a light traveling direction, so that a thermal lens can be reversibly formed in the light absorption layer due to a temperature increase occurring in a region where the control light is absorbed and its peripheral region, and the refractive index of the thermal lens changes to change a traveling direction of the signal light, wherein two or more control light beams are emitted into the light absorption layer so that the traveling direction of the signal light can be changed based on a combination of two or more control beams.