Optical deflection method and optical deflection apparatus

An optical deflection apparatus comprising:

• a signal light source configured to emit signal light having one or more wavelengths;
• a control light source configured to emit control light having a wavelength different from the wavelength of the signal light;
• a thermal lens forming optical element including a light absorption layer configured to transmit the signal light and selectively absorb the control light;
• and
• a beam-condensing unit configured to cause beam-condensation of the control light and the signal light at different convergence points in the light absorption layer,
• wherein the thermal lens forming optical element causes 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, wherein a thermal lens is 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.

An optical path switching method comprising:

• selecting emission of control light according to desired information;
• emitting the 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 in a direction perpendicular to an optical axis, wherein a wavelength of the control light differs 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;
• 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 thermal lens changes a refractive index to change a traveling direction of the signal light;
• and
• separately outputting first signal light having a traveling direction not changed by the emission of the control light and second signal light having a traveling direction changed by the emission of the control light depending on respective traveling directions.

An optical path switching apparatus, comprising:

• a signal light source configured to emit signal light having one or more wavelengths;
• a control light source configured to emit control light having a wavelength different from the wavelength of the signal light;
• a thermal lens forming optical element including a light absorption layer configured to transmit the signal light and selectively absorb the control light;
• and
• a beam-condensing unit configured to cause beam-condensation of the control light and the signal light at different convergence points in the light absorption layer in a direction perpendicular to an optical axis,
• wherein the thermal lens forming optical element causes convergence and divergence of the control light and the signal light on an incidence plane of the light absorption layer or its vicinity in alight traveling direction, wherein a thermal lens is 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 thermal lens changes a refractive index to change a traveling direction of the signal light,
• wherein the optical path switching apparatus further comprises:
• an output unit configured to separately output a first signal light having a traveling direction not changed by the emission of the control light and a second signal light having a traveling direction changed by the emission of the control light depending on respective traveling directions.

An optical path switching method, comprising:

• selecting emission of control light according to desired information;
• emitting the 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 in a direction perpendicular to an optical axis, 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 thermal lens changes a refractive index to change a traveling direction of the signal light, and
• detecting first signal light having a traveling direction not changed by the emission of the control light and second signal light having a traveling direction changed by the emission of the control light which are beam-condensed or converged by a same optical system.

An optical path switching apparatus comprising:

• a signal light source configured to emit signal light having one or more wavelengths;
• a control light source configured to emit control light having a wavelength different from the wavelength of the signal light;
• a thermal lens forming optical element including a light absorption layer configured to transmit the signal light and selectively absorb the control light;
• and
• a beam-condensing unit configured to cause beam-condensation of the control light and the signal light at different convergence points in the light absorption layer in a direction perpendicular to an optical axis,
• wherein the thermal lens forming optical element causes 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, wherein a thermal lens is 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 thermal lens changes a refractive index to change a traveling direction of the signal light,
• wherein the optical path switching apparatus further comprises:
• an optical detection unit configured to receiving first signal light having a traveling direction not changed by the emission of the control light and second signal light having a traveling direction changed by the emission of the control light which are beam-condensed or converged by a same optical system.