Device for transporting and controlling light pulses for lensless endo-microscopic imaging

Patent metadata

Field	Value
Publication number	US-2018011309-A1
Application number	US-201515536881-A
Country	US
Kind code	A1
Filing date	Dec 17, 2015
Priority date	Dec 18, 2014
Publication date	Jan 11, 2018
Grant date	—

Abstract

According to one aspect, the invention concerns a device for transporting and controlling light pulses for lensless endo-microscopic imaging and comprises:
a bundle of N monomode optical fibers (F 1 ) arranged in a given pattern, each monomode optical fiber being characterized by a relative group delay value (Ax) defined relative to the travel time of a pulse propagating in a reference monomode optical fiber (F 0 ) of the bundle of fibers ( 40 ), an optical device for controlling group velocity ( 50 ) comprising a given number M of waveplates (P j ) characterized by a given delay (8t j ); a first spatial light modulator ( 51 ) suitable for forming from an incident light beam a number N of elementary light beams (B i ) each of which is intended to enter into one of said optical fibers, each elementary beam being intended to pass into a given waveplate such that the sum of the delay introduced by said waveplate and the relative group delay of the optical fiber intended to receive said elementary light beam is minimal in absolute value; a second spatial light modulator ( 52 ) suitable for deviating each of the N elementary light beams such that each elementary light beam penetrates into the corresponding optical fiber perpendicularly to the entrance face of the optical fiber.

First claim

1 . A device for transporting and controlling light pulses having at least one first wavelength for lensless endo microscopic imaging, comprising:
a bundle of N monomode optical fibers arranged in a given pattern, intended to receive a light beam formed of pulses at a proximal end and to emit a light beam at a distal end, each monomode optical fiber being characterized by a relative group delay value defined relative to the travel time of a pulse propagating in a reference monomode optical fiber of the bundle of fibers, an optical device for group velocity control, disposed on the proximal side of the optical fibers bundle and comprising:
a given number M of waveplates, each waveplate enabling the introducing of a given delay;
a first spatial light modulator suitable for forming from one or more incident light beams a number N of elementary light beams, each elementary beam being intended to enter into one of said optical fibers and to pass into a given waveplate such that the sum of the delay introduced by said waveplate and the relative group delay of the optical fiber intended to receive said elementary light beam is minimal in absolute value;
a second spatial light modulator suitable for deviating each of the N elementary light beams such that each elementary light beam penetrates into the corresponding optical fiber perpendicularly to the entrance face of the optical fiber; and
a phase control device comprising means of programming of the one and/or the other of the spatial light modulators, making possible the application of a phase shift to each of the elementary beams to imprint at the distal end of the bundle of fibers a predetermined phase function and/or to correct the phase variations introduced by each of the fibers of the bundle of fibers.

2 . The device for transporting and controlling light pulses according to claim 1 , wherein the optical device for controlling the group velocity comprises a first lens and a second lens forming an optical layout with an intermediate focal plane and in which:
the waveplates are disposed in the intermediate focal plane of the optical layout; the first spatial light modulator is located in an object focal plane of the first lens; and the second spatial light modulator is located in an image focal plane of the second lens.

3 . The device for transporting and controlling light pulses according to claim 1 , wherein the optical device for controlling the group velocity comprises a lens and in which:
the waveplates are disposed in a plane situated upstream from the first spatial light modulator and are adapted to form, from an incident beam formed of pulses, M light beams, each light beam being formed of pulses characterized by a given group delay; the first spatial light modulator is arranged in the object focal plane of the lens and is intended to receive said M light beams; and the second spatial light modulator is located in an image focal plane of the lens.

4 . The device for transporting and controlling light pulses according to claim 3 , wherein the first spatial light modulator is formed from M holographic zones, each holographic zone being intended to receive one of said light beams formed of pulses characterized by a given group delay.

5 . The device for transporting and controlling light pulses according to claim 1 , wherein the bundle of N monomode optical fibers is formed by a multi-core fiber.

6 . The device for transporting and controlling light pulses according to claim 1 , wherein the N monomode optical fibers are maned ire aperiodic manner.

7 . An endo-microscopic imaging system, comprising:
a source of light pulses; a device for transporting and controlling the pulses emitted by said source according to claim 1 ; and a detection path for the light intended to pass through the bundle of monomode optical fibers from its distal end to its proximal end.

8 . A method of nonlinear lensless endo-microscopic imaging by means of a bundle of monomode optical fibers arranged in a given pattern, wherein each monomode optical fiber is characterized by a relative group delay value defined relative to the travel time of a pulse propagating in a reference monomode optical fiber of the bundle of fibers, the method comprising:
the emitting of an incident beam formed of pulses having at least one wavelength at a first spatial light modulator arranged in the object focal plane of a first lens forming with a second lens an optical layout with an intermediate focal plane; the formation by means of the first spatial light modulator from the incident light beam of a number N of elementary light beams, wherein each elementary beam is intended to enter into one of said optical fibers, and each elementary beam passes into a given waveplate characterized by a delay and arranged in the intermediate focal plane of the optical layout, such that the sum of the delay introduced by said waveplate and the relative group delay of the optical fiber intended to receive said elementary light beam is minimal in absolute value; the deviating by means of a second spatial light modulator arranged in the image focal plane of the second lens of each of the N elementary light beams such that each elementary light beam penetrates into the corresponding optical fiber perpendicularly to the entrance face of the optical fiber; the application of a phase shift to each of the elementary beams by the one or the other of the first and second spatial light modulators to imprint at the distal end of the bundle of fibers a predetermined phase function and/or to correct the phase variations introduced by each of the fibers of the bundle of fibers.

9 . A method of nonlinear lensless endo-microscopic imaging by means of a bundle of monomode optical fibers arranged in a given pattern and each monomode optical fiber being characterized by a relative group delay value defined relative to the travel time of a pulse propagating in a reference monomode optical fiber of the bundle of fibers, the method comprising:
the emitting of an incident beam formed of pulses having at least one wavelength and the formation, from said incident beam and by means of M waveplates each one characterized by a delay, of a number M of light beams, each of the M light beams being formed of pulses characterized by a given group delay, the formation, by means of a first spatial light modulator arranged in the object focal plane of a first lens and from the M light beams, of a number N of elementary light beams, wherein each elementary light beams is intended to enter into one of said optical fibers, such that the sum of the delay of the light beam from which is formed the elementary light beam so introduced and the relative group delay of the optical fiber intended to receive said elementary light beam is minimal in absolute value; the deviating, by means of a second spatial light modulator arranged in the image focal plane of the lens, of each of the N elementary light beams such that each elementary light beam penetrates into the corresponding optical fiber perpendicularly to the entrance face of the optical fiber; the application of a phase shift to each of the elementary beams by the one or the other of the first and second spatial light modulators to imprint at the distal end of the bundle of fibers a predetermined phase function and/or to correct the phase variations introduced by each of the fibers of the bundle of fibers.

10 . The method of nonlinear lensless endo-microscopic imaging according to claim 8 , involving the emitting of at least two incident light beams, each incident light beam being formed of pulses having a distinct wavelength, and wherein the first spatial light modulator furthermore allows a distri

Assignees

• Centre National De La Recherche Scient (Cnrs)
• Université D'Aix-Marseille
• Centre Nat Rech Scient

Inventors

• Andresen Esben
• Rigneault Hervé

Classifications

• G02B6/065

  with dynamic image improvement · CPC title

• G02B6/06

  the relative position of the fibres being the same at both ends, e.g. for transporting images · CPC title

• G02B21/0004

  specially adapted for specific applications · CPC title

• H01S3/0057

  Temporal shaping, e.g. pulse compression, frequency chirping (soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108) · CPC title

• G02B6/02042

  Multicore optical fibres · CPC title