Patent ID: 11940416
Assignee: NEDERLANDSE ORGANISATIE VOOR TOEGEPAST-NATUURWETENSCHAPPELIJK ONDERZOEK TNO
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 7:
8. A scanning probe microscopy system for imaging structures on or below the surface of a sample, the system comprising:
a probe for scanning the sample surface, wherein the probe comprises a probe tip mounted on a cantilever, and wherein the probe is mounted on a sensing head arranged for bringing the probe tip in contact with the sampling surface;
a motion actuator for enabling motion of the probe relative to the sample;
a transducer for applying, using a coupling medium and contacting the sample, an acoustic input signal directly to the sample, wherein the coupling medium is different from the probe and the probe tip; and
a probe deflection sensor for producing a sensor signal indicative of an acoustic output signal received via the probe tip, wherein the acoustic output signal is representative of acoustic waves induced by the acoustic input signal,
wherein the transducer is arranged for producing the acoustic input signal so as to comprise at least a first signal component having a first frequency above 1 gigahertz,
wherein the system is further configured for 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 system is configured for applying the further acoustic input signal by inducing acoustic vibrations in the probe tip of the probe, and
wherein the system comprises an optical excitation source configured for producing and directing an optical excitation beam to be incident on the probe tip, the optical excitation source being configured for producing 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.