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Optical microscopy has a diffraction limited resolution of about 250 nm. Fluorescence methods (e.g. PALM, STORM, STED) beat this, but they are still limited to 10 s of nm, and the images are an indirect pointillist representation of only…

We suggest a new multimodal imaging technique for quantitatively measuring the integral (thickness-average) refractive index of the nuclei of live biological cells in suspension. For this aim, we combined quantitative phase microscopy with…

We have developed a white light interferometric microscope (WLIM), which can spatially resolve the change in the complex index of refraction and apply it to study reversible photodegradation of 1,4-Diamino-9,10-anthraquinone doped into…

Optics · Physics 2015-06-16 Benjamin Anderson , Elizabeth Bernhardt , Mark G. Kuzyk

Confocal Raman microscopy, a highly specific and label-free technique for the microscale study of thick samples, often presents difficulties due to weak Raman signals. Inhomogeneous samples introduce wavefront aberrations that further…

Pixel size in cameras and other refractive imaging devices is typically limited by the free-space diffraction. However, a vast majority of semiconductor-based detectors are based on materials with substantially high refractive index. We…

Optics · Physics 2018-03-28 Bo Fan , Sandeep Inampudi , Viktor A. Podolskiy

We present an accurate determination of the refractive index of hydrogen, helium, H2O and neon up to 35 GPa at ambient temperature. The experimental method is based on the combination of two interferometric signals of the Fabry-Perot cavity…

Materials Science · Physics 2009-11-07 A. Dewaele , J. Eggert , P. Loubeyre , R. Le Toullec

Determination of refractive index of micro-disks of a calcinated ($1100^\circ$C in air) photo-resist SZ2080$^\mathrm{TM}$ was carried out using transmission and reflection spectroscopy. Interference fringes at specific…

Screening of unknown particles, including viruses and nanoparticles, is key in medicine, industry and pollutant determination. However, existing techniques require sample a priori knowledge or modification (e.g. fluorescence). Here we…

Label-free optical imaging is valuable in biology and medicine with its non-destructive property and reduced optical and chemical damages. Quantitative phase (QPI) and molecular vibrational imaging (MVI) are the two most successful…

We propose a coherent optical method for creating negative refractive index (NRI) for a gaseous ensemble of ground-state polar molecules possessing both permanent electric and magnetic moments. Exploiting the pure rotational transition…

Measuring the average refractive index (RI) of spherical objects, such as suspended cells, in quantitative phase imaging (QPI) requires a decoupling of RI and size from the QPI data. This has been commonly achieved by determining the…

Quantitative Methods · Quantitative Biology 2018-04-27 Paul Müller , Mirjam Schürmann , Salvatore Girardo , Gheorghe Cojoc , Jochen Guck

In this work, we demonstrate an integrated platform comprising a refractive index (RI) sensor based on Photonic Molecule (PM) that effectively mitigates the influence of environmental perturbations using a differential measurement scheme…

We present broadband cavity-enhanced complex refractive index spectroscopy (CE-CRIS), a technique for calibration-free determination of the complex refractive index of entire molecular bands via direct measurement of transmission modes of a…

Photonic integrated circuit devices can be used as refractometric opto-fluidic sensors to detect the presence of analytes in solution at low concentrations. In this work, we investigate the refractive index sensitivity of silicon nitride…

The photo-kinetics of fluorescent molecules have enabled the circumvention of far-field optical diffraction-limit. Despite its enormous potential, the necessity to label the sample may adversely influence the delicate biology under…

Optical reflection microscopy is one of the main imaging tools to visualize graphene microstructures. Here is reported a novel method that employs refractive index optimization in an optical reflection microscope, which greatly improves the…

Mesoscale and Nanoscale Physics · Physics 2013-05-29 H. Gonçalves , L. Alves , C. Moura , M. Belsley , T. Stauber , P. Schellenberg

Non-contact measurement of the refractive index and thickness of multilayer biological tissues is of great significance for biomedical applications and can greatly improve medical diagnosis and treatment. In this work, we introduce a…

Optics · Physics 2024-04-19 Yu-Lin Ku , Yao-Gen Shu

A new numerically and experimentally tested measurement method for the local electrical light field including its phase is presented. The method is based on Self Referencing Interferograms (SRI) such as shearing interferograms. The complex…

Instrumentation and Detectors · Physics 2016-10-27 Martin Berz , Cordelia Berz

We demonstrate aqueous refractive index sensing with 15 to 30 {\mu}m diameter silicon nitride microdisk resonators to detect small concentrations of Li salt. A dimpled-tapered fiber is used to couple 780 nm visible light to the microdisks,…

Mesoscale and Nanoscale Physics · Physics 2015-04-06 C. Doolin , P. Doolin , B. C. Lewis , J. P. Davis

The detection of spatial or temporal variations in very thin samples has important applications in the biological sciences. For example, cellular membranes exhibit changes in lipid composition and order, which in turn modulate their…