Method and apparatus for processing a minute portion of a specimen

• US 5,333,495 A
• Filed: 03/11/1993
• Issued: 08/02/1994
• Est. Priority Date: 05/30/1990
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamaguchi, Hiroshi, Nakata, Toshihiko, Noguchi, Minori, Kohno, Makiko
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): Dombroske, George M.
• Application Number:
  US08/012,758
• Time in Patent Office: 509 Days
• Field of Search: 73/105, 73/801, 73/643, 250/306, 250/307, 250/492.2 R, 250/492.21
• US Class Current: 73/105
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: G01N 25/18 by investigating thermal conductivity by calorimetry G01N25/20; by measuring change of resistance of an electrically-heated body G01N27/18
• CPC Class Codes: G01Q 30/02 Non-SPM analysing devices, e.g. SEM [Scanning Electron Microscope], spectrometer or optical microscope
• CPC Class Codes: G01Q 60/22 Probes, their manufacture, or their related instrumentation, e.g. holders
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence
• CPC Class Codes: Y10S 977/859 including substrate treatment
• CPC Class Codes: Y10S 977/861 Scanning tunneling probe
• CPC Class Codes: Y10S 977/862 Near-field probe
• CPC Class Codes: Y10S 977/879 Material

Abstract

A method for detecting a photoacoustic signal includes the steps of modulating the intensity of light obtained from a light source at a predetermined modulation frequency, exciting a specimen by directing the intensity-modulated light onto the specimen, thereby generating a photoacoustic effect in the specimen, detecting the photoacoustic effect generated in the specimen and producing a detection signal indicative of the detected photoacoustic effect, and extracting information about the surface and interior of the specimen from the detection signal, wherein the intensity-modulated light is emitted from an aperture of a near-field optical scanning microscope used in directing the intensity-modulated light onto the specimen while a distance between the aperture of the near-field optical scanning microscope and the surface of the specimen is maintained constant irrespective of the photoacoustic effect generated in the specimen.

Claims

1. A method for detecting a photoacoustic signal comprising the steps of:

modulating the intensity of light obtained from a light source at a predetermined modulation frequency;

exciting a specimen by directing said intensity-modulated light onto the specimen, thereby generating a photoacoustic effect in the specimen;

detecting the photoacoustic effect generated in the specimen and producing a detection signal indicative of the detected photoacoustic effect; and

extracting information about the surface and interior of the specimen from said detection signal;

wherein the intensity-modulated light is emitted from an aperture of a near-field optical scanning microscope used in directing said intensity-modulated light onto the specimen while a distance between the aperture of the near-field optical scanning microscope and the surface of the specimen in maintained constant irrespective of the photoacoustic effect generated in the specimen.

2. A method for detecting a photoacoustic signal according to claim 1, wherein a scanning tunneling microscope is used in detecting the photoacoustic effect.

3. A method for detecting a photoacoustic signal according to claim 1, wherein light reflected from the specimen surface of light transmitted through the specimen is detected by a near-field optical scanning microscope, and the detected light is used in detecting the photoacoustic effect.

4. A method for detecting a photoacoustic signal according to claim 1, wherein an interferometer which includes a near-field optical scanning microscope is used in detecting the photoacoustic effect.

5. An apparatus for detecting a photoacoustic signal comprising:

a light source;

modulation means for modulating the intensity of light from said light source at a predetermined modulation frequency;

exciting means for exciting a specimen by directing said intensity-modulated light onto the specimen, thereby generating a photoacoustic effect in the specimen;

detection means for detecting the photoacoustic effect generated in the specimen and producing a detection signal indicative of the detected photoacoustic effect; and

information extracting means for extracting information about the surface and interior of the specimen from the detection signal produced by said detection means;

wherein said exciting means includes a near-field optical scanning microscope, and wherein the intensity-modulated light is emitted from an aperture of the near-field optical scanning microscope while a distance between the aperture of the near-field optical scanning microscope and the surface of the specimen is maintained constant irrespective of the photoacoustic effect generated in the specimen.

6. An apparatus for detecting a photoacoustic signal according to claim 5, wherein said detection means includes a scanning tunneling microscope.

7. An apparatus for detecting a photoacoustic signal according to claim 5, wherein light reflected from the specimen surface or light transmitted through the specimen is detected by a near-field optical scanning microscope, and the detected light is used by said detection means in detecting the photoacoustic effect.

8. An apparatus for detecting a photoacoustic signal according to claim 5, wherein said detection means is an interferometer which includes a near-field optical scanning microscope.