Wavelength conversion device and light source device

1. A light source device comprising:

a wavelength conversion element having a phosphor plate configured to convert a wavelength of incident light upon a light incident surface to generate wavelength-converted light, and emit the wavelength-converted light from a light emission surface;

an antenna array comprising a plurality of optical antennas that are periodically arranged on said light emission surface of said phosphor plate;

a recessed structure including at least one recessed portion provided in said light emission surface of said phosphor plate; and

a light source which generates light to be incident upon said light incident surface of said phosphor plate,

wherein said plurality of optical antennas are arranged with a period corresponding to a wavelength of the wavelength-converted light in said phosphor plate, and

wherein said at least one recessed portion comprises a groove arranged within the antenna array.

2. The light source device according to claim 1 , wherein said at least one recessed portion has a rough interior wall surface.

3. The light source device according to claim 1 , wherein a depth of said at least one recessed portion is larger than a height of said optical antennas.

4. The light source device according to claim 1 , wherein said at least one recessed portion has a side surface that is inclined with respect to said light emission surface of said phosphor plate.

5. The light source device according to claim 1 , wherein:

said optical antennas are arranged in a square lattice, and

said groove extends in a lattice form along arrangement directions of said optical antennas.

6. The light source device according to claim 1 , wherein said phosphor plate has an inclined side surface that is tapered from said light emission surface toward said light incident surface.

7. The light source device according to claim 1 , wherein said phosphor plate comprises a ceramic plate made of a single-phase phosphor.

8. The light source device according to claim 1 , further comprising a light reflective portion provided in said at least one recessed portion of said recessed structure.

9. The light source device according to claim 1 , wherein said wavelength conversion element has a light reflective film provided on a side surface of said phosphor plate.

10. The light source device according to claim 1 , further comprising:

a light reflective structure provided on said light incident surface of said phosphor plate, the light reflective structure having transparency to the light incident from said light incident surface and reflectivity to the wavelength-converted light;

a support which supports said wavelength conversion element through said light reflective structure; and

an anti-reflective structure provided on said support on a surface opposite to said light reflective structure.

11. The light source device according to claim 1 , wherein said light source is a laser source which generates a laser beam.

12. A wavelength conversion device comprising:

a wavelength conversion element having a phosphor plate configured to convert a wavelength of incident light upon a light incident surface to generate wavelength-converted light, and emit the wavelength-converted light from a light emission surface;

an antenna array comprising a plurality of optical antennas that are arranged in one direction with a predetermined pitch on said light emission surface of said phosphor plate; and

a recessed structure including at least one recessed portion provided in an area extending in a direction perpendicular to said one direction on said light emission surface of said phosphor plate,

wherein said at least one recessed portion comprises a groove arranged within the antenna array.