Bruker Nano Gmbh

Anasys Instruments Corporation

Honghua Yang

Craig Prater

Kevin Kjoller

Sam Berweger

Alexandre Dazzi

Anirban Roy

A method for obtaining optical spectroscopic information about a sub-micron region of a sample with quantitatively controlled depth/volume of the sample subsurface using a scanning probe microscope. With controlled probing depth/volume, the method can separate top surface data from subsurface optical/chemical information. The method can also be applied in liquid suitable for studying biological and chemical samples in their native aqueous environments, as opposed to air. In the method, a depth-controlled spectrum of the surface layer is constructed by illuminating the sample with a beam of infrared radiation and measuring a probe response using at least one of the resonant frequencies of the probe. The surface sensitivity is obtained by limiting the heat diffusion effect of the subsurface so as to confine the signal. The signal confinement is achieved through non-linearity of the acoustic wave with probe, as well as benefits gained by a high modulation frequency of the infrared radiation source at &#x3e;1 MHz.

Method and apparatus of atomic force microscope based infrared spectroscopy with controlled probing depth

Systems and methods may be provided for measuring an infrared absorption of a sub micrometer region of a sample. An Infrared light source may illuminate a sample in a region that is interacting with the tip of a Scanning Probe Microscope (SPM), stimulating the sample in a way that produces measurable optical properties related to Infrared absorption of the sample region. A probe light source is directed at the region of the sample and SPM tip, and probe light emanating from the tip and sample region is collected. The collected light may be used to derive infrared absorption spectrum information of the sample region, possibly on a sub-micron scale.

Method and apparatus for infrared scanning near-field optical microscopy based on photothermal effect

System and method for measuring an optical property of a sub micrometer region of a sample including interacting a probe tip of a probe microscope with a region of the sample, illuminating the sample with a beam of light from a radiation source such that light is scattered from the probe-sample interaction region, interfering a reference beam with the scattered light wherein the reference beam has an adjustable optical phase, measuring with a detector at least a portion of the light scattered from probe-sample and background regions at a substantially constant reference phase, and constructing a signal indicative of the optical property of the sample wherein contributions from background scattered light are substantially suppressed.

Method and apparatus for infrared scattering scanning near-field optical microscopy with background suppression

This invention involves measurement of optical properties of materials with sub-micron spatial resolution through infrared scattering scanning near field optical microscopy (s-SNOM). Specifically, the current invention provides substantial improvements over the prior art by achieving high signal to noise, high measurement speed and high accuracy of optical amplitude and phase. Additionally, it some embodiments, it eliminates the need for an in situ reference to calculate wavelength dependent spectra of optical phase, or absorption spectra. These goals are achieved via improved asymmetric interferometry where the near-field scattered light is interfered with a reference beam in an interferometer. The invention achieves dramatic improvements in background rejection by arranging a reference beam that is much more intense than the background scattered radiation. Combined with frequency selective demodulation techniques, the near-field scattered light can be efficiently and accurately discriminated from background scattered light. These goals are achieved via a range of improvements including a large dynamic range detector, careful control of relative beam intensities, and high bandwidth demodulation techniques. In other embodiments, phase and amplitude stability are improved with a novel s-SNOM configuration. In other embodiments an absorption spectrum may be obtained directly by comparing properties from a known and unknown region of a sample as a function of illumination center wavelength.

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Santa Barbara, CA, United States of America

Honghua Yang