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EP-3742151-B1 - SCANNING PROBE MICROSCOPE

EP3742151B1EP 3742151 B1EP3742151 B1EP 3742151B1EP-3742151-B1

Inventors

  • SHIGEKAWA, HIDEMI

Dates

Publication Date
20260506
Application Date
20190118

Claims (3)

  1. A scanning probe microscope (1;1A) comprising: a pump light output unit (2) that emits pump light (21) having a first specified phase to a specimen (900) and performs emission of the pump light (21) a plurality of number of times to excite the specimen (900); a probe light output unit (3) that emits probe light (31) having a second specified phase to the specimen (900) once while the specimen (900) is excited by one-time emission of the pump light (21); and a scanning probe (5) that detects, from the specimen (900), a probe signal corresponding to each one-time emission of the probe light (31), wherein the pump light output unit (2) or the probe light output unit (3) includes a delay time adjustment unit (3A) that adjusts delay time from a start of the emission of the pump light (21) until a start of the emission of the probe light (31), wherein the probe light output unit (3) includes a modulation unit (3B) that is configured to modulate the probe light by controlling the carrier-envelope phase (CEP) of the probe light, and wherein the scanning probe microscope (1;1A) further comprises a lock-in detector (5A) that extracts a component synchronized with the probe light (31) modulated by the probe light modulation unit (3B) from the probe signal.
  2. The scanning probe microscope (1;1A) according to claim 1, wherein the pump light (21) which is output in one-time emission by the pump light output unit (2) includes less than one cycle of waves with dominant intensity.
  3. The scanning probe microscope (1;1A) according to any one of claims 1 to 2, wherein the probe light (31) which is output in one-time emission by the probe light output unit (3) includes less than one cycle of waves with dominant intensity.

Description

TECHNICAL FIELD The present invention relates to a scanning probe microscope. BACKGROUND ART Conventionally, there has been provided an Optical Pump-Probe Scanning Tunneling Microscopy (OPP-STM) as an apparatus for acquiring time-resolved information of a specimen through atomic- and molecular-level spatial resolutions. With the OPP-STM, a tunneling current flowing between a probe and the specimen is read as a probe signal while emitting a pulse pair immediately below the probe. Consequently, a surface phenomenon of the specimen can be analyzed in a femtosecond region. For example, JP 2013-32993 discloses a pump probe measuring apparatus including: an ultrashort light pulse laser generation unit that generates a first ultrashort light pulse train which becomes pump light, a second ultrashort light pulse train which has first delay time with respect to the pump light and becomes probe light, and a third ultrashort light pulse train which has second delay time with respect to the pump light and becomes probe light; a light shutter unit into which the second and third ultrashort light pulse trains enter; a light shutter control unit that controls the light shutter unit; an irradiation optical system that emits the pump light and the probe light to a specimen; and a detection unit including a sensor for detecting a probe signal from the specimen, and a phase-sensitive detection means coupled to the sensor, wherein the second ultrashort light pulse train and the third ultrashort light pulse train are alternately emitted as the probe light to the specimen by the light shutter control unit by cyclically modulating the delay time of the probe light with respect to the pump light, and the probe signal is synchronized with the cyclic modulation of the delay time and then detected by the phase-sensitive detection means. EP 2 741 072 A1 and EP 2 090 880 A1 disclose a pump probe measuring device and a scanning probe microscope apparatus using the device. Hidemi Shigekawa et al, "Optical pump probe STM", KEMBIKYOU = MICROSCOPY, JP, (20170101), vol. 52, no. 1, discloses an optical pump-probe STM. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION The inventors have found a new challenge that it is necessary to precisely evaluate quantum dynamics of a photoinduced carrier, including charge transfer, transition, and conduction, in order to further promote the advancement of nanoscale science technology and develop new functions. However, the invention described in JP 2013-32993 cannot observe the dynamics while it's controlling. MEANS TO SOLVE THE PROBLEMS The invention is defined in claim 1. The dependent claims describe optional embodiments of the invention. ADVANTAGEOUS EFFECTS OF THE INVENTION The quantum dynamics can be controlled and observed according to the present invention. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a diagram illustrating a schematic configuration of an electron microscope 1 according to a first example that is not part of the claimed invention;Fig. 2 is an enlarged view of an area around the tip of a scanning probe 5;Fig. 3 (a) is a diagram illustrating a time waveform of pump light 21; and Fig. 3 (b) is a diagram illustrating a frequency spectrum of the pump light 21;Fig. 4 is a schematic diagram illustrating time variation of the pump light 21 and probe light 31 according to the first example that is not part of the claimed invention;Fig. 5 is a diagram illustrating the distance between the tip of a cantilever and a specimen 900 in Variation 1;Fig. 6 is a schematic diagram illustrating time variation of the pump light 21 and the probe light 31 in Variation 5;Fig. 7 is a diagram illustrating a schematic configuration of an electron microscope 1A according to an embodiment of the claimed invention;Fig. 8 is a diagram illustrating the configuration of a modulation unit 3B when performing on-off keying;Fig. 9 is a diagram illustrating the configuration of the modulation unit 3B when performing phase modulation;Fig. 10 is a schematic diagram illustrating time variation of the pump light 21 and the probe light 31 according to a second example that is not part of the claimed invention; andFig. 11 is a schematic diagram illustrating time variation of the pump light 21 and the probe light 31 according to Variation 2 of the second example that is not part of the claimed invention. DESCRIPTION OF EMBODIMENTS - First example that is not part of the claimed invention - A first example that is not part of the claimed invention of an electron microscope which is a scanning probe microscope will be explained below with reference to Fig. 1 to Fig. 4. Fig. 1 is a diagram illustrating a schematic configuration of an electron microscope 1. The electron microscope 1 includes a pump light output unit 2, a probe light output unit 3, and a scanning probe 5. The pump light output unit 2 and the probe light output unit 3 operate in synchronization with each other as described later. The probe light output unit