Adjustable speed fast laser scanning system and two-photon microscope associated

Patent metadata

Field	Value
Publication number	US-2016274440-A1
Application number	US-201415034553-A
Country	US
Kind code	A1
Filing date	Nov 7, 2014
Priority date	Nov 8, 2013
Publication date	Sep 22, 2016
Grant date	—

Abstract

The present invention concerns a laser scanning system ( 18 ) comprising: —a first acousto-optical deflector ( 30 ) deflecting a beam in a first direction (X) to obtain a first deflected beam and comprising a first acousto-optical crystal on which is applied an acoustic wave whose frequency varies over time according to a first law of command, and —a second acousto-optical deflector ( 32 ) deflected the first deflected beam in a second direction (Y), defining an angle comprised between 85° and 95° with the first direction, and comprising a second acousto-optical crystal on which is applied an acoustic wave whose frequency varies over time according to a second law of command, characterized in that the first law of command and the second law of command are chosen so that the average speed of the laser scanning system ( 18 ) is superior to 10 radians per second.

First claim

1 . Laser scanning system comprising:
a first acousto-optical deflector adapted to deflect an input beam in a first direction to obtain a first deflected beam, the first acousto-optical deflector comprising a first acousto-optical crystal and a first transducer adapted to command the first acousto-optical crystal by applying a first acoustic wave having a variation in frequency over time according to a first law of command, and a second acousto-optical deflector adapted to deflect the first deflected beam in a second direction to obtain a second deflected beam, the first direction and the second direction define at least an angle comprised between 85° and 95° and the second acousto-optical deflector comprising a second acousto-optical crystal and a second transducer adapted to command the second acousto-optical crystal by applying a second acoustic wave having a variation in frequency over time according to a second law of command,
characterized in that the first law of command and the second law of command are chosen so that the speed of the laser scanning system is superior to 10 radians per second and in that the two acousto-optic deflectors introduce a defocusing in the input beam and the laser scanning system comprises a compensating unit for compensating the defocusing introduced by the two acousto-optic deflectors.

2 . The laser scanning system according to claim 1 , wherein the compensating unit comprises a spherical lens and a translation device for modifying the position of the spherical lens with respect to the two acousto-optic deflectors.

3 . The laser scanning system according to claim 1 , wherein the angle, between the first direction and the second direction, is equal to 90°.

4 . The laser scanning system according to claim 1 , wherein the first law of command and the second law of command are chosen so that the speed of the laser scanning system is superior to 20 radians per second, preferably 50 radians per second.

5 . The laser scanning system according to claim 1 , wherein the optical distance between the first acousto-optical crystal and the second acousto-optical crystal along the third direction is inferior to 30 millimeters, preferably inferior to 15 millimeters.

6 . The laser scanning system according to claim 1 , wherein the local averaged slope of the first law of command over time is comprised between 95% and 105% of a first constant value.

7 . The laser scanning system according to claim 1 , wherein the local averaged slope of the second law of command over time is comprised between 95% and 105% of a second constant value.

8 . The laser scanning system according to claim 6 , wherein the local averaged slope of the second law of command over time is comprised between 95% and 105% of a second constant value, and wherein the first constant value and the second constant value are equal.

9 . The laser scanning system according to claim 1 , wherein the first law of command and the second law of command are linear functions of time.

10 . The laser scanning system according to claim 1 , wherein the first law of command and the second law of command are step functions of time.

11 . The laser scanning system according to claim 10 , wherein for each law of command, the step functions are intervals of constant frequency separated by a step, wherein each acousto-optic deflector has an optical resolution and wherein the largest frequency step between two intervals of constant frequency is inferior to the highest of these optical resolutions.

12 . A two-photon microscope comprising a laser scanning system according to claim 1 .

Assignees

• Inst Nat De La Sante Et De La Rech Medicale (Inserm)
• Centre Nat De La Rech Scient (C N R S)
• Ecole Normale Superieure

Inventors

• Dieudonne Stéphane
• Mathieu Benjamin

Classifications

• G02F1/3526

  using two-photon emission or absorption processes · CPC title

• G02F1/33 Primary

  Acousto-optical deflection devices {(circuit or control arrangements therefor G02F1/113)} · CPC title

• G02F2001/291

  Physics · mapped topic

• G02B27/0031

  for scanning purposes · CPC title

• G02B21/004

  fixed arrays, e.g. switchable aperture arrays · CPC title