We propose a method for ultra-sensitive displacement and phase metrology based on the interferometric evanescent wave excitation of nano-antennas. We show that with a proper choice of nano-antenna, tiny displacements or relative phase variations can be converted into sensitive scattering direction changes in the Fourier $k$-space. These changes stem from the strong position dependence of the imaginary Poynting vector orientation within interfering evanescent waves. Using strongly-evanescent standing waves, high sensitivity is achieved in the nano-antenna's zero scattering direction, which varies linearly with displacement over a long range. With weakly-evanescent wave interference, even higher sensitivity to tiny displacement or phase changes can be reached around chosen location. The high sensitivity of the proposed method can form the basis for many applications.
Higher resolution demands for semiconductor lithography may be fulfilled by higher numerical aperture (NA) systems. However, NAs more than the photoresist refractive index (~1.7) cause surface confinement of the image. In this letter we describe how evanescent wave coupling to effective gain medium surface states beneath the imaging layer can counter this problem. At λ=193 nm a layer of sapphire on SiO2 counters image decay by an effective-gain-medium resonance phenomena allowing evanescent interferometric lithography to create high aspect ratio structures at NAs of 1.85 (26-nm) and beyond.
Abbe's resolution limit, one of the best-known physical limitations, poses a great challenge for any wave systems in imaging, wave transport, and dynamics. Originally formulated in linear optics, this Abbe's limit can be broken using nonlinear optical interactions. Here we extend the Abbe theory into a nonlinear regime and experimentally demonstrate a far-field, label-free, and scan-free super-resolution imaging technique based on nonlinear four-wave mixing to retrieve near-field scattered evanescent waves, achieving sub-wavelength resolution of $λ/15.6$. This method paves the way for applicat…
Evanescent waves are central to many technologies such as near-field imaging that beats the diffraction limit and plasmonic devices. Frustrated total internal reflection (FTIR) is an experimental method commonly used to study evanescent waves. In this paper, we shape the incident beam of the FTIR process with a Mach-Zehnder interferometer and measure light transmittance while varying the path length difference and interferometric visibility. Our results show that the transmittance varies with the path length difference and, thus, the intensity distribution of the shaped beam. Experiment and fi…
We present the experimental test of a method for controlling the absolute length of the diagonals of square ring laser gyroscopes. The purpose is to actively stabilize the ring cavity geometry and to enhance the rotation sensor stability in order to reach the requirements for the detection of the relativistic Lense-Thirring effect with a ground-based array of optical gyroscopes. The test apparatus consists of two optical cavities 1.32 m in length, reproducing the features of the ring cavity diagonal resonators of large frame He-Ne ring laser gyroscopes. The proposed measurement technique is ba…
We improve the precision of the interferometric weak-value-based beam deflection measurement by introducing a power recycling mirror, creating a resonant cavity. This results in \emph{all} the light exiting to the detector with a large deflection, thus eliminating the inefficiency of the rare postselection. The signal-to-noise ratio of the deflection is itself magnified by the weak value. We discuss ways to realize this proposal, using a transverse beam filter and different cavity designs.
Photothermal Fourier-plane Phase Synchronization for Interferometric Scattering Microscopy
Huazhong University of Science and Technology（华中科技大学）；Wuhan National Laboratory for Optoelectronics（武汉光电国家研究中心）；Institute of Photonics and Electronics of the Czech Academy of Sciences（捷克科学院光子学与电子学研究所）
Interferometric phase measurement is widely used to precisely determine quantities such as length, speed, and material properties. Without quantum correlations, the best phase sensitivity $Δφ$ achievable using $n$ photons is the shot noise limit (SNL), $Δφ=1/\sqrt{n}$. Quantum-enhanced metrology promises better sensitivity, but despite theoretical proposals stretching back decades, no measurement using photonic (i.e. definite photon number) quantum states has truly surpassed the SNL. Rather, all such demonstrations --- by discounting photon loss, detector inefficiency, or other imperfections -…
As a consequence of a general trend in the physics of oscillators and clocks towards optics, phase and frequency metrology is rapidly moving to optics too. Yet, optics is not replacing the traditional radio-frequency (RF) and microwave domains. Instead, it adds tough challenges. Precision frequency-stability measurements are chiefly based on the measurement of phase noise, which is the main focus of this article. Major progress has been achieved in two main areas. The first is the extreme low-noise measurements, based on the bridge (interferometric) method in real time or with sophisticated co…
Recently, Motes et al. proposed in Phys. Rev. Lett. 114, 170802 (2015) a linear optics interferometer with N identical single photon input states as a tool for sub-shot-noise phase estimation which does not require NOON states sources. This thesis investigates how the degree of distinguishability between the input photonic spectra affects the interferometric phase sensitivity, by employing the results obtained by Tamma and Laibacher in Phys. Rev. Lett. 114, 243601 (2015). Remarkably, the obtained results show, that for small phases, the phase sensitivity in the case of completely distinguishab…
The ability of spatial light modulators (SLMs) to modify the amplitude and phase of light has proved them invaluable to the optics and photonics community. In many applications the bit-depth of SLMs is a major limiting factor dictated by the digital processor. As a result, there is usually a compromise between refresh speed and bit-depth. Here we present a method to increase the effective bit-depth of SLMs which utilizes a linear slope as is commonly applied to deal with the zeroth order effect. This technique was tested using two interferometric transient absorption spectroscopy setups. Throu…
Evanescent light can be localized at the nanoscale by resonant absorption in a plasmonic nanoparticle or taper or by transmission through a nanohole. However, a conventional lens cannot focus free-space light beyond half of the wavelength λ. Nevertheless, precisely tailored interference of multiple waves can form a hotspot in free space of arbitrarily small size known as superoscillation. Here, we report a new type of integrated metamaterial interferometry that allows for the first time mapping of fields with deep subwavelength resolution ~ λ/100. It reveals that electromagnetic field near the…
Efficient Many-Body Shadow Metrology via Clifford Lensing
Indian Institute of Technology Bombay（印度理工学院孟买分校）；Indian Institute of Science Education and Research, Pune（印度科学教育研究所浦那分校）；ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology（ICFO-光子科学研究院，巴塞罗那科学技术研究院）
Recent progress has boosted the resolving power of optical microscopies to spatial dimensions well below the diffraction limit. Yet, axial super-resolution and axial single-molecule localisation typically require more complicated implementations than their lateral counterparts. In the present work, we propose a simple solution for axial metrology by providing a multi-layered single-excitation, dual-emission test slide, in which axial distance is colour-encoded. Our test slide combines on a standard microscope coverslip substrate two flat, thin, uniform and brightly emitting fluorophore layers,…
Multimodal Fusion Network for Micro-displacement Measurement via Michelson Interferometer
School of Physics and Astronomy, Sun Yat-Sen University（中山大学物理学院）；MOE Key Laboratory of TianQin Mission, TianQin Research Center for Guangdong Gravitational Physics, Frontiers Science Center for TianQin, Gravitational Wave Research Center of CNSA, Sun Yat-sen University（中山大学天琴任务教育部重点实验室、广东省引力物理天琴研究中心、天琴前沿科学中心、中国航天局引力波研究中心）
The Laser Interferometer Space Antenna (LISA) and its metrology chain have to fulfill stringent performance requirements to enable the space-based detection of gravitational waves. This implies the necessity of performance verification methods. In particular, the extraction of the interferometric phase, implemented by a phasemeter, needs to be probed for linearity and phase noise contributions. This Letter reports on a hexagonal quasimonolithic optical bench implementing a three-signal test for this purpose. Its characterization as sufficiently stable down to picometer levels is presented as w…
