Transmission-type angle deviation microscopy

Abstract

We present a new microscopy technique that we call transmission angle deviation microscopy (TADM). It is based on common-path heterodyne interferometry and geometrical optics. An ultrahigh sensitivity surface plasmon resonance (SPR) angular sensor is used to expand dynamic measurement ranges and to improve the axial resolution in three-dimensional optical microscopy. When transmitted light is incident upon a specimen, the beam converges or diverges because of refractive and/or surface height variations. Advantages include high axial resolution (approximately 32 nm), nondestructive and noncontact measurement, and larger measurement ranges (+/- 80 microm) for a numerical aperture of 0.21 in a transparent measurement medium. The technique can be used without conductivity and pretreatment.

System analysis of full-field reflection-type three-dimensional angle-deviation microscope

“…A 3D optical microscope has white-light interferometry or optical coherence tomography (OCT) [2][3][4]. Other methods used in 3D microscopy include confocal microscopy [5,6], near-field scanning optical microscopy (NSOM) [7], and laser-scanning angle-deviation microscopy (ADM) [8,9]. Confocal microscopy is well known for its confocal optical system in optical scanning microscopes.…”

Lateral and axial resolutions of an angle-deviation microscope for different numerical apertures: experimental results

“…It is smaller than that of the case presented before (Ref. 6, in which the heterodyne light source is composed of a He-Ne laser, an The sample is a periodic pattern with a ZnO coating. The period is 6 μm and the line-width is 3 μm.…”

“…In 2008, we reported on transmission-type angle-deviation microscopy (TADM), in which NA = 0.21 (Ref. 6) when the lateral resolutions reach 0.8 μm. In order to further improve the measurement accuracy and resolution of TADM, we increased the NA value of the objectives and used a Zeeman laser as a light source to decrease noise caused by lowfrequency interference so that the lateral and axial resolution could reach 0.5 μm and 3 nm, respectively.…”

Full-field transmission-type angle-deviation optical microscope with reflectivity-height transformation

“…The system could be used for the characterization of internal reflection effect [4] near the critical angle in a prism to measure the reflectivity, thereby leading to the computation of the ray angle and the height of surface. This method differs greatly from traditional ones such as the White-Light Interferometry, the Optical Coherence Tomography (OCT) [5][6][7], Confocal Microscopy [8,9], NSOM: Near-field Scanning Optical Microscopy [10], and Laser-scanning Angle-deviation Microscopy (ADM) [11,12]. Among these reported methods, confocal microscopy [8,9] is best known as an optical scanning microscope.…”

“…Since the signal is captured in smaller than a wavelength, it can overcome the diffraction limit and achieve nanometers of lateral resolution. The scanning type of ADM [11,12] combines surface plasmon resonance (SPR) wave with high-phase sensitivity and common-path heterodyne interferometry (CPHI) [13] with real-time and high-phase analytical characteristics. When the measuring point is out of the focal plane, the light beam will produce either divergence or convergence phenomenon.…”