Beam expander

Patent metadata

Field	Value
Publication number	US-10067401-B2
Application number	US-201314395167-A
Country	US
Kind code	B2
Filing date	Apr 18, 2013
Priority date	Apr 20, 2012
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

A beam expander includes a first lens unit including one of an SLM or a VFL, a second lens unit being optically coupled to the first lens unit and including one of an SLM or a VFL, and a control unit controlling focal lengths of the first and second lens units. A distance between the first and second lens units is invariable. The control unit controls the focal lengths of the first and second lens units such that a light diameter D 1 of light input to the first lens unit and a light diameter D 2 of light output from the second lens unit are different from each other.

First claim

The invention claimed is:

1. A beam expander comprising:
a first lens unit;
a second lens unit; and
a control unit configured to control a focal length f 1 of the first lens unit and a focal length f 2 of the second lens unit, wherein
the first lens unit and the second lens unit are composed of a single reflection type spatial light modulator having a single light-reflecting surface, a first region of the light-reflecting surface comprises the first lens unit, and a second region of the light-reflecting surface comprises the second lens unit,
the first lens unit is optically coupled to the second lens unit by light modulated by the first lens unit being input to the second lens unit,
a distance L 1 between the first lens unit and the second lens unit is invariable, and
the control unit controls the focal lengths of the first lens unit and the second lens unit by providing a lens pattern to the single reflection type spatial light modulator such that:
a light diameter of input light input to the first lens unit and a light diameter of output light output from the second lens unit are different from each other,
the light diameter of the output light is changed with respect to the light diameter of the input light, and
the focal lengths f 1 and f 2 and the distance L 1 satisfy the relationship f 2 =L 1 −f 1 .

2. The beam expander according to claim 1 , wherein the control unit provides the lens pattern with which a straight line including a central axis line of light input to the first lens unit and a straight line including a central axis line of light output from the second lens unit are separated from one another, to the single reflection type spatial light modulator.

3. The beam expander according to claim 1 , wherein the control unit provides the lens pattern with which, with respect to light input to the first lens unit, light output from the second lens unit is split into a plurality of optical paths, to the single reflection type spatial light modulator.

4. The beam expander according to claim 1 , wherein the control unit superimposes a pattern for correcting aberrations generated in the beam expander, onto the lens pattern to be provided to the single reflection type spatial light modulator.

5. The beam expander according to claim 1 , wherein a light diameter of input light incident into the first lens unit is ½ or less of a length of an effective surface of the first lens unit.

6. The beam expander according to claim 1 , comprising a plurality of reflective elements, wherein the second lens unit is optically coupled to the first lens unit via the plurality of reflective elements.

Assignees

• Hamamatsu Photonics Kk

Inventors

• Matsumoto Naoya
• Inoue Takashi
• Takiguchi Yuu

Classifications

• G02B26/06

  for controlling the phase of light (G02B26/08 takes precedence {, measuring optical phase difference G01J9/00}) · CPC title

• G02F1/29 Primary

  for the control of the position or the direction of light beams, i.e. deflection · CPC title

• G02B27/56

  Optics using evanescent waves, i.e. inhomogeneous waves · CPC title

• G02B26/0875

  by means of one or more refracting elements · CPC title

• G02B27/0927

  Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat · CPC title