US 11,940,416 B2
Heterodyne scanning probe microscopy method and system
Hamed Sadeghian Marnani, 's-Gravenhage (NL); Maarten Hubertus van Es, Voorschoten (NL); Paul Louis Maria Joseph van Neer, Bergschenhoek (NL); and Rutger Meijer Timmerman Thijssen, Loosdrecht (NL)
Assigned to Nederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO, 's-Gravenhage (NL)
Appl. No. 16/093,285
Filed by Nederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO, 's-Gravenhage (NL)
PCT Filed Apr. 13, 2017, PCT No. PCT/NL2017/050228
§ 371(c)(1), (2) Date Oct. 12, 2018,
PCT Pub. No. WO2017/179978, PCT Pub. Date Oct. 19, 2017.
Claims priority of application No. 16165292 (EP), filed on Apr. 14, 2016.
Prior Publication US 2019/0204276 A1, Jul. 4, 2019
Int. Cl. G01N 29/06 (2006.01); G01N 29/24 (2006.01); G01N 29/34 (2006.01); G01N 29/44 (2006.01); G01Q 60/32 (2010.01); G01Q 60/34 (2010.01)
CPC G01N 29/0681 (2013.01) [G01N 29/2406 (2013.01); G01N 29/2418 (2013.01); G01N 29/346 (2013.01); G01N 29/4436 (2013.01); G01Q 60/32 (2013.01); G01Q 60/34 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A heterodyne scanning probe microscopy method for imaging structures on or below the surface of a sample, the method including:
applying, using a transducer and a coupling medium in contact with the sample, an acoustic input signal directly to the sample;
sensing, using a probe including a probe tip in contact with the surface, an acoustic output signal, wherein the probe and probe tip are different from the coupling medium, and wherein the acoustic output signal is representative of acoustic waves induced by the acoustic input signal that are measurable at the surface;
wherein the acoustic input signal comprises at least a first signal component having a first frequency above 1 gigahertz,
wherein, for detecting of the acoustic output signal during the sensing, the method further comprises applying a further acoustic input signal to the probe for obtaining a mixed acoustic signal, the further acoustic input signal including at least a second signal component having a second frequency above 1 gigahertz,
wherein the mixed acoustic signal comprises a third signal component having a third frequency equal to a difference between the first frequency and the second frequency,
wherein the third frequency of the third signal component is below 1 gigahertz,
wherein the further acoustic input signal is applied by inducing acoustic vibrations in the probe tip of the probe, and
wherein the inducing acoustic vibrations in the probe tip is performed by producing and directing an optical excitation beam to be incident on the probe tip, the optical excitation beam having a time varying optical power at the second frequency above 1 gigahertz for enabling photo thermal excitation of the probe tip for the inducing acoustic vibrations.