Laser scanning optical system and laser scanning optical apparatus

• US 5,796,112 A
• Filed: 08/09/1996
• Issued: 08/18/1998
• Est. Priority Date: 06/03/1993
• Status: Expired due to Fees

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: Ichie, Koji
• Primary Examiner(s): FIELDS, CAROLYN
• Application Number:
  US08/699,058
• Time in Patent Office: 739 Days
• Field of Search: 359/196, 250/458.1, 250/459.1, 250/461.1, 250/461.2, 356/317, 356/318, 356/417
• US Class Current: 250/458.1
• CPC Class Codes: G02B 21/0032 Optical details of illumination, e.g. light-sources, pinholes, beam splitters, slits, fibers G02B21/0036 - G02B21/008; means for illumination of specimens in general G02B21/06
• CPC Class Codes: G02B 21/0072 details concerning resolution or correction, including general design of CSOM objectives
• CPC Class Codes: G02B 21/0076 arrangements using fluorescence or luminescence
• CPC Class Codes: G02B 21/0084 time-scale detection, e.g. strobed, ultra-fast, heterodyne detection
• CPC Class Codes: G02B 21/16 adapted for ultraviolet illumination ; Fluorescence microscopes G02B21/0076 takes precedence
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 27/09 Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for adapting the beam shape of a laser diode G02B19/0052; adapting the beam shape of an LED G02B19/0061; coupling into light guides using intermediate optical elements G02B6/4204; beam shaping specially adapted for lasers H01S3/005
• CPC Class Codes: G02B 27/0911 Anamorphotic systems
• CPC Class Codes: G02B 27/0972 Prisms prisms per se G02B5/04
• CPC Class Codes: G02B 5/001 Axicons, waxicons, reflaxicons

Abstract

A fluorescent microscope includes a laser scanning unit having a stage for supporting a fluorescent sample, a laser beam generator and a beam scanning unit for causing a laser beam from the generator to spot scan a sample to cause fluorescence generated by multi-photon absorption. A first detector detects fluorescence emitted from a side of the sample on which the laser beam is incident to output a first signal corresponding to detected fluorescence. A second detector detects fluorescence emitted from a side of the sample from which the laser beam, having been transmitted through the sample, is emitted from the sample. The second detector produces a second signal corresponding to the detected fluorescence. The first and second signals are summed and amplified. A display is provided for a microscopic image of the sample in synchronization with the scanning of the laser beam, based on the amplified summed signals.

Claims

1. A fluorescence microscope comprising:

a laser scanning unit including;

a stage for supporting a fluorescence sample thereon;

a laser beam generator; and

a beam scanning unit for causing a laser beam from said laser beam generator to spot scan a sample to cause fluorescence generated by multiphoton absorption;

a first detector for detecting fluorescence emitted from a laser beam incident side of said sample to output a first signal corresponding to the detected fluorescence;

a second detector for detecting fluorescence emitted from a laser beam transmitted side of the sample to output a second signal corresponding to the detected fluorescence;

means for summing and amplifying the first and second signals; and

means for displaying a microscopic image of the sample in synchronization with scanning of the laser beam based on the amplified summed signals.

2. A fluorescence microscope according to claim 1,

wherein said laser beam generator comprises an optical converting unit for shaping a laser beam incident thereinto as a beam of parallel rays into a cylindrical ray bundle thereof;

and

wherein said beam scanning unit comprises;

an optical scanning part for changing a traveling direction of said laser beam incident from said optical converting unit thereinto to scan; and

an optical converging part for converging said laser beam incident from said optical scanning part thereinto to produce a Bessel beam, said optical converting part comprising two axicon prisms which are arranged such that apexes thereof are opposed forward or backward to each other at a predetermined distance and optical axes thereof are coincident with each other and which are made of respective materials having a same refractive index and shaped with a same apical angle.

3. A fluorescence microscope according to claim 2, wherein said optical converting part has moving means for variably setting a distance between said two axicon prisms.

4. A fluorescence microscope according to claim 2, further comprising a beam expander disposed either on the entrance side or on the exit side of said optical converting part, for expanding a diameter of the ray bundle of said laser beam.

5. A fluorescence microscope according to claim 2, further comprising a beam reducer disposed either on the entrance side or on the exit side of said optical converting unit, for reducing a diameter of the ray bundle of said laser beam.

6. A fluorescence microscope according to claim 1, wherein said laser beam generator provides a pulsed laser beam, the pulses having a very short time duration, and wherein said sample is labeled with a predetermined fluorescence dye.