Heterodyne technique in photoinduced force microscopy with photothermal effect

Yamanishi, Junsuke; Naitoh, Yoshitaka; Li, Y. J.

doi:10.1063/1.4978755

Cited by 29 publications

(29 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The first eigenmode of the cantilever is excited by the interaction forces between the sample and the tip, which are induced by the external laser source. This interaction is detected in the cantilever mechanics when the laser intensity is modulated at the frequency difference between the first and second eigenmode resonances 20 , 21 . In this case, the laser (QCL from Block Engineering) is p-polarized, the pulse width is 20 ns, and the light wavenumber (wavelength) can be tuned between 795 and 1900 cm −1 .…”

Section: Resultsmentioning

confidence: 98%

Selective excitation and imaging of ultraslow phonon polaritons in thin hexagonal boron nitride crystals

et al. 2018

View full text Add to dashboard Cite

We selectively excite and study two new types of phonon-polariton guided modes that are found in hexagonal boron nitride thin flakes on a gold substrate. Such modes show substantially improved confinement and a group velocity that is hundreds of times slower than the speed of light, thereby providing a new way to create slow light in the mid-infrared range with a simple structure that does not require nano-patterning. One mode is the fundamental mode in the first Restrahlen band of hexagonal boron nitride thin crystals on a gold substrate; the other mode is equivalent to the second mode of the second Restrahlen band of hexagonal boron nitride flakes that are suspended in vacuum.The new modes also couple efficiently with incident light at the hexagonal boron nitride edges, as we demonstrate experimentally using photo-induced force microscopy and scanning near-field optical microscopy. The high confinement of these modes allows for Purcell factors that are on the order of tens of thousands directly above boron nitride and a wide band, with new perspectives for enhanced light-matter interaction. Our findings demonstrate a new approach to engineering the dispersion of polaritons in 2D materials to improve confinement and light-matter interaction, thereby paving the way for new applications in mid-infrared nano-optics.

show abstract

Section: Resultsmentioning

confidence: 98%

Selective excitation and imaging of ultraslow phonon polaritons in thin hexagonal boron nitride crystals

et al. 2018

View full text Add to dashboard Cite

show abstract

“…The numerical analyses reveal that due to their phase difference, photothermal and photovoltage effects add or subtract their action on the cantilever, depending on the DC field sign. These findings are of relevance for all AFM techniques which use an optical excitation of the cantilever sensor, and for the emergent field of photoinduced force microscopy [31][32][33][34][35] in particular, as well as for other opto-mechanical systems where intrinsic or externally controlled electrostatic fields and light absorption are involved.…”

mentioning

confidence: 75%

Photonic Excitation of a Micromechanical Cantilever in Electrostatic Fields

et al. 2020

View full text Add to dashboard Cite

We present a specific near-field configuration where an electrostatic force gradient is found to strongly enhance the optomechanical driving of an atomic force microscope cantilever sensor. It is shown that incident photons generate a photothermal effect which couples with electrostatic fields even at tip-surface separations as large as several wavelengths, dominating the cantilever dynamics. The effect is the result of resonant phenomena where the photothermal-induced parametric driving acts conjointly (or against, depending on electric field direction) with a photovoltage generation in the cantilever. The results are achieved experimentally in an atomic force microscope operating in vacuum and explained theoretically through numerical simulations of the equation of motion of the cantilever. Intrinsic electrostatic effects arising from electronic work-function difference of tip and surface are also highlighted. The findings are readily relevant for other opto-micromechanical systems where electrostatic force gradients can be implemented.

show abstract

“…213, 214 This heterodyne detection is reported to improve imaging contrast, as compared to direct detection at the modulation frequency (f m ), and effectively avoid artifacts caused by photothermal effects. 215 Figure 10 shows a general schematic of PiFM experimental setup. More theoretical details and early experiments of PiFM are summarized in previous reports.…”

Section: Pifmmentioning

confidence: 99%