Scanning probe microscope utilizing an optical element in a waveguide for dividing the center part of the laser beam perpendicular to the waveguide

• US 5,231,286 A
• Filed: 08/22/1991
• Issued: 07/27/1993
• Est. Priority Date: 08/31/1990
• Status: Expired due to Fees

• Current Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Original Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Inventors: Tazaki, Hiroshi, Funazaki, Jun, Nakamura, Yasushi, Saito, Keisuke, Tomabechi, Hideo, Kajimura, Hiroshi
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): DAVENPORT, TERESA
• Application Number:
  US07/748,687
• Time in Patent Office: 705 Days
• Field of Search: 250/216, 250/234, 250/306, 250/307, 250/328
• US Class Current: 250/234
• CPC Class Codes: G01Q 20/02 by optical means
• CPC Class Codes: Y10S 977/837 Piezoelectric property of nanomaterial
• CPC Class Codes: Y10S 977/868 with optical means
• CPC Class Codes: Y10S 977/869 Optical microscope
• CPC Class Codes: Y10S 977/87 Optical lever arm for reflecting light
• CPC Class Codes: Y10S 977/873 Tip holder
• CPC Class Codes: Y10S 977/951 Laser

Abstract

A scanning probe microscope according to the present invention comprises a cantilever having a free end portion and a fixed end portion, the free end portion bearing a probe thereon, a semiconductor laser attached to the fixed end portion of the cantilever, an optical waveguide for guiding a laser beam, emitted from the semiconductor laser, to the free end portion, an optical element for dividing part of a center beam of the laser beam, guided through the optical waveguide, into laser beams in at least two perpendicular directions, a photoelectric transducer for receiving the divided laser beams and converting the laser beams into electrical output signals corresponding thereto, and a differential circuit for receiving the electrical signals and subjecting the signals to predetermined arithmetic processing, thereby detecting a three-dimensional displacement of the free end portion of the cantilever.

Claims

1. A scanning probe microscope comprising:

a probe supporting member having a free end portion and a fixed end portion the free end portion bearing a probe thereon;

a laser light source attached to the fixed end portion of the probe supporting member;

an optical waveguide for guiding a laser beam, emitted from the laser light source, to the free end portion;

an optical element arranged in the optical waveguide, for dividing the laser beam into laser beams in at least two perpendicular directions;

a photoelectric transducer for receiving the divided laser beams and for converting the laser beams into electrical output signals corresponding thereto; and

arithmetic processing means for receiving the electrical signals and subjecting the signals to predetermined arithmetic processing.

2. A scanning probe microscope comprising:

a probe supporting member having a free end portion and a fixed end portion, the free end portion bearing a probe thereon;

a laser light source attached to the fixed end portion of the probe supporting member;

an optical waveguide for guiding a laser beam, emitted from the laser light source, to the free end portion; and

a photoelectric transducer for receiving the laser beam delivered thereto via the free end portion and for converting the laser beam into an electrical output signal corresponding thereto.

5. A scanning probe microscope according to claim 2, wherein said probe supporting member comprises a cantilever in the form of a thin rectangular plate.

6. A scanning probe microscope according to claim 2, wherein said optical waveguide comprises means for dividing the laser beam guided through the optical waveguide into a center beam and side beams on either side thereof.

7. A scanning probe microscope according to claim 6, wherein the cross-sectional area of said center beam accounts for approximately 70% of the total cross-sectional area of the laser beam guided through the optical waveguide, and that of each said side beam for approximately 15% of the total cross-sectional area.

8. A scanning probe microscope according to claim 7, wherein said optical waveguide includes a half mirror for reflecting part of the center beam in a direction perpendicular to an optical axis of the optical waveguide and for transmitting the remainder in the direction of the optical axis, and a Fresnel lens body for reflecting the center beam transmitted through the half mirror, in a direction perpendicular to the center beam reflected by the half mirror.

3. A scanning probe microscope comprising:

a probe supporting member having a free end portion and a fixed end portion, the free end portion bearing a probe thereon;

a laser light source attached to the fixed end portion of the probe supporting member;

an optical waveguide for guiding a laser beam, emitted from the laser light source, to an opening in a distal end face of the free end portion;

a first photoelectric transducer for receiving the laser beam emitted from the opening and converting the laser beam into an electrical output signal;

an optical element arranged in the optical waveguide, for deflecting the laser beam in a direction perpendicular to the longitudinal axis of the optical waveguide;

a second photoelectric transducer for receiving the laser beam deflected by means of the optical element and converting the laser beam into an electrical output signal; and

arithmetic processing means for receiving the electrical signals and subjecting the signals to predetermined arithmetic processing.

4. A scanning probe microscope comprising:

a probe supporting member having a free end portion and a fixed end portion, the free end portion bearing a probe thereon;

a laser light source attached to the fixed end portion of the probe supporting member;

an optical waveguide for guiding a laser beam, emitted from the laser light source, to an opening in a distal end face of the free end portion; and

a photoelectric transducer for receiving the laser beam emitted from the opening and converting the laser beam into an electrical output signal.

9. A scanning probe microscope according to claim 4, wherein said probe supporting member comprises a cantilever in the form of a thin rectangular plate.

10. A scanning probe microscope according to claim 4, wherein said optical waveguide comprises means for dividing the laser beam guided through the optical waveguide into a center beam and side beams on either side thereof.

11. A scanning probe microscope according to claim 10, wherein the cross-sectional area of said center beam accounts for approximately 70% of the total cross-sectional area of the laser beam guided through the optical waveguide, and that of each said side beam for approximately 15% of the total cross-sectional area.

12. A scanning probe microscope according to claim 11, wherein said optical waveguide comprises a half mirror of 50% transmittance for reflecting part of the center beam in a direction perpendicular to the optical axis of the optical waveguide and for transmitting the remainder in the direction of the optical axis.

13. A scanning probe microscope according to claim 11, wherein said optical member comprises a Fresnel lens body of 90°

reflection angle for reflecting the center beam transmitted through the half mirror, in a direction perpendicular to the center beam reflected by the half mirror.

14. A scanning probe microscope comprising:

a probe supporting member having a free end portion and a fixed end portion, the free end portion bearing a probe thereon;

a laser light source attached to the fixed end portion of the probe supporting member and emitting a laser beam to the free end portion;

an optical element arranged on said free end portion, for dividing the laser beam into laser beams in at least two perpendicular directions;

a photoelectric transducer for receiving the divided laser beams and converting the laser beams into electrical output signals corresponding thereto; and

arithmetic processing means for receiving the electrical signals and subjecting the signals to predetermined arithmetic processing.