Object characterization with a differential heterodyne microscope

Akhmedzhanov, I. M.; Baranov, D. V.; Zolotov, Evgenii M

doi:10.1088/1464-4258/5/5/365

Cited by 9 publications

(7 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The basics of the SDHM operation (Fig1) has already been discussed at length in previous publications [15,17], so that we can simply reiterate the main SDHM features: (i) the common-path optical interferometric microscopy with coherent optical detection, which involves two probe beams with the intermediate (heterodyne) frequency shift: f i ~ 0.1 -4 MHz, (ii) the distance δ between the probe beams in the object plane (typically ~ 0.1 -4 μm) can conveniently be adjusted by varying the frequency shift, (iii) the object is located at the front focal plane of the objective with the point-like photodetector positioned at the Fourier plane of the objective, and (iv) the phase and amplitude response determined by the sample reflectivity is detected at the intermediate frequency f i . Overall, these features ensure rather reliable and robust optical characterisation of the sample reflectivity via registration of both phase and amplitude components of the differential optical response.…”

Section: Sdhm Responsementioning

confidence: 99%

“…Within the thin phase-amplitude screen approximation [15,16], the output current of the point photodetector (coherent registration scheme) at the center of the objective Fourier plane contains both amplitude and phase information directly related to the amplitude and phase of a complex response function [15,17]:…”

Section: Sdhm Responsementioning

confidence: 99%

“…Generally speaking, the phase and amplitude reflection characteristics of the sample surface are encoded in the SDHM phase and amplitude responses in a rather complicated manner that does not allow them to be separately retrieved. Even the direct problem of finding the SDHM response for a given reflectivity profile within the thin phase-amplitude screen approximation requires numerical simulations using the above formulae [15]. Nevertheless, there is one particularly important configuration, a sample surface with a purely phase profile featuring a constant reflection phase gradient G (i.e., the case of an ideal phase-gradient reflective metasurface designed for the beam steering [21]), that can analytically be dealt with.…”

Section: mentioning

confidence: 99%

“…The SDHM seems therefore very well suited for the characterization of reflective phase-gradient metasurfaces, in general, and gap-plasmon based gradient metasurfaces, in particular. Generally speaking, the SDHM can be considered as the modification of conventional far-field scanning optical microscopy (SOM) with the additional possibility of accurately determining spatial gradients in the phase of reflected optical beams [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Scanning differential microscopy for characterization of reflecting phase-gradient metasurfaces

Akhmedzhanov

Bozhevolnyi²

2018

Optics Communications

View full text Add to dashboard Cite

Gap-plasmon based phase-gradient metasurfaces operating in reflection are widely used for the realization of diverse flat optical components, ranging from spectropolarimeters to efficient couplers for surface waves. Successful implementation of carefully designed metasurfaces is however often hampered by technological imperfections that could be related to deviations of geometrical parameters of fabricated nanostructures from the designed ones or material properties, such as the metal and/or dielectric susceptibilities, from the handbook data. While the overall performance of fabricated components might indicate the existence of a potential problem, it is very difficult to identify its origin, which, for example, can simply be related to the deviation in only one cell of the metasurface supercell. We suggest exploiting well-developed experimental techniques of scanning differential heterodyne microscopy (SDHM) to characterize fabricated phase-gradient metasurfaces designed to operate in reflection. We further establish that, by carefully measuring the SDHM response of a gradient metasurface, one should be able of detecting small (~ 5%) amplitude and phase deviations (with respect to the design values) in the optical field reflected by an individual subwavelength-sized cell of the metasurface supercell. Research highlights Сomplex scanning differential heterodyne microscope (SDHM) response of phase-gradient metasurfaces operating in reflection is numerically investigated, revealing a direct relationship between the SDHM phase response and the average phase gradient of the metasurface. Furthermore, we establish that small (~ 5%) amplitude and phase deviations (from the design values) in the complex reflection of an individual subwavelength-sized cell of the metasurface supercell can be detected by analysing the SDHM response.

show abstract

Section: Sdhm Responsementioning

confidence: 99%

Section: Sdhm Responsementioning

confidence: 99%

Section: mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Scanning differential microscopy for characterization of reflecting phase-gradient metasurfaces

Akhmedzhanov

Bozhevolnyi²

2018

Optics Communications

View full text Add to dashboard Cite

show abstract

“…It is possible to measure the topography in sub-nanometer level by using optical interferometric techniques (Somekh et al 1995). Among these, differential heterodyne interferometer (DHI) has a good point for non-contact characterization of micro-objects and surface profiling (Akhmedzhanov et al 2003). Also, DHI is able to measure a step height and line width of a sample with high resolution.…”

Section: Description Of the Proposed System Differential Heterodyne Imentioning

confidence: 99%

Beam Scanning Confocal Differential Heterodyne Interferometry

Song

Kim

Gweon

2007

International Journal of Optomechatronics

View full text Add to dashboard Cite

This article presents a new approach to the design of confocal differential heterodyne interferometer (CDHI), which is a combination of differential heterodyne interferometer (DHI) with confocal laser scanning microscopy (CLSM). The CDHI can measure a step height over a quarter of wavelength of the light source, which can not be accurately measured by DHI and CLSM, respectively. The approach is that it utilizes a beam-scanning method instead of transporting a sample to be measured. The measurement results carried out for samples having step height are found to be comparable in precision with those measured by commercial scanning electron microscopes.

show abstract

Modeling of step-like object images in scanning differential heterodyne microscope using rigorous diffraction theory

2004

Self Cite

View full text Add to dashboard Cite

A theory of the image formation for a scanning differential heterodyne microscope is presented using the rigorous diffraction theory for perfectly conducting arbitrary-surfaced object. Computed results are compared with experimental responses to a step-like object with the 0.35 µm height and the 0.3 µm transition. The superresolving object characterization is analyzed using a variation of step parameters. An enhancement of microscope sensitivity using an adjustment of the interval between probing spots and choosing the polarization state of probing beams is investigated. The responses obtained with the rigorous method and those obtained by means of the scalar diffraction theory are compared. The experimental responses (dashed line) to the metalized step with the 0.35 µm height and 0.3 µm transition and simulated responses using integral method (1) and scalar approximation (2).

show abstract

Object characterization with a differential heterodyne microscope

Cited by 9 publications

References 4 publications

Scanning differential microscopy for characterization of reflecting phase-gradient metasurfaces

Scanning differential microscopy for characterization of reflecting phase-gradient metasurfaces

Beam Scanning Confocal Differential Heterodyne Interferometry

Modeling of step-like object images in scanning differential heterodyne microscope using rigorous diffraction theory

Contact Info

Product

Resources

About