Laser driven lamp

1. A laser driven lamp configured to enclose light emitting gas, receive a converging laser beam and generate plasma from the laser beam, the laser driven lamp comprising:

a main body having a columnar shape;

a concave reflecting portion formed at a front side of the main body, the concave reflecting portion having a focal point at which the laser beam converges;

a light exit window provided in front of the concave reflecting portion;

a laser beam passing hole formed at a center of the main body, the laser beam passing hole penetrating the main body in an optical axial direction of the lamp;

a light entrance window provided at a rear side of the main body, the laser beam being incident to the light entrance window; and

a tapered part at a light incident side of the laser beam passing hole in the main body,

the main body, the light exit window and the light entrance window constituting in combination a closed space, and

the light emitting gas being enclosed in the closed space.

2. The laser driven lamp according to claim 1 , further comprising a reflective part formed at a center of the light exit window and configured to reflect the laser beam.

3. The laser driven lamp according to claim 1 , further comprising a gas release pipe attached to the lamp, the gas release pipe communicating with the closed space in the main body.

4. The laser driven lamp according to claim 3 , further comprising a window attaching cylindrical body being made from a metal, wherein the window attaching cylindrical body attaches the light entrance window and the light exit window to the main body, respectively, and

the gas release pipe being attached to the window attaching cylindrical body.

5. The laser driven lamp according to claim 3 , wherein the main body is made of ceramic, and

the gas release pipe is attached to the main body.

6. The laser driven lamp according to claim 3 , wherein the light entrance window is attached to the main body with a metallic block being interposed between the light entrance window and the main body, and

the gas release pipe is attached to the metallic block.

7. The laser driven lamp according to claim 1 , wherein a laser light incidence plane surface of the light entrance window is inclined with respect to an optical path of the laser beam.