Previously, we presented an on-axis linear-response linear-motion optical scanner. While the linear design is highly desired for engineering consideration, it was still lacking the scanning speed required for imaging applications. We here present a customized profile lens (CPL), tailored for high speed performance while maintaining the advantages of a linear response on-axis optical scanner. The device was built and tested experimentally on an optical bench. The test results demonstrate precise linear response and fast scanning speed, and revealed video frame rate scanning ability. The implementation of the CPLs in laser scanning systems is promising in improving the current 3D laser scanning microscopy systems by reducing the size, error, and complexity of the system, as well as other systems unitizing high speed laser scanning technique.
Many applications in various fields of science and engineering use steered optical beam systems. Currently, many methods utilize mirrors in order to steer the beam. However, this approach is an off-axis solution, which normally increases the total size of the system as well as its error and complexity. Other methods use a “Risely Prisms” based solution, which is on-axis solution, however it poses some difficulties from an engineering standpoint, and therefore isn't widely used. We present here a novel technique for steering a beam on its optical axis with a linear deflection response. We derived the formulation for the profile required of the refractive optical component necessary for preforming the beam steering. The functionality of the device was simulated analytically using Matlab, as well as using a ray-tracing software, Zemax, and showed agreement with the analytical model. An optical element was manufactured based on the proposed design and the device was tested. The results show agreement with our hypothesis. We also present some proposed geometries of the several other devices, all based on the same concept, which can be used for higher performance applications such as two-dimensional scanner, video rate scanner etc.
In recent years, interest in studying the components of the cornea and their arrangement, with emphasis
on the corneal stroma, has expanded rapidly. By determining the corneal stroma’s organization in detail, we will understand better the relationship between its structure and functionality. Here, the
cornea’s collagen lamellae were scanned using second harmonic generation (SHG) microscopy, in order to determine the orientation of fibers in different directions within a two-dimensional cross section. A unique algorithm was used to quantitatively measure the directions. Cross sections were
obtained at several different depths in each sample. This work offers supplemental sectioning
revelations to the methods historically used to scan at the lamella level, such as X-ray diffraction.
The stepwise multiphoton activated fluorescence (SMPAF) of melanin, activated by a continuous-wave mode near infrared (NIR) laser, reveals a broad spectrum extending from the visible spectra to the NIR and has potential application for a low-cost, reliable method of detecting melanin. SMPAF images of melanin in mouse hair and skin are compared with conventional multiphoton fluorescence microscopy and confocal reflectance microscopy (CRM). By combining CRM with SMPAF, we can locate melanin reliably. However, we have the added benefit of eliminating background interference from other components inside mouse hair and skin. The melanin SMPAF signal from the mouse hair is a mixture of a two-photon process and a third-order process. The melanin SMPAF emission spectrum is activated by a 1505.9-nm laser light, and the resulting spectrum has a peak at 960 nm. The discovery of the emission peak may lead to a more energy-efficient method of background-free melanin detection with less photo-bleaching.
Confocal microscopy can be used as a practical tool in non-invasive applications in medical diagnostics and
evaluation. In particular, it is being used for the early detection of skin cancer to identify pathological cellular
components and, potentially, replace conventional biopsies. The detection of melanin and its spatial location and
distribution plays a crucial role in the detection and evaluation of skin cancer. Our previous work has shown that the
visible emission from melanin is strong and can be easily observed with a near-infrared CW laser using low power. This
is due to a unique step-wise, (SW) three-photon excitation of melanin. This paper shows that the same SW, 3-photon
fluorescence can also be achieved with an inexpensive, continuous-wave laser using a dual-prism scanning system. This
demonstrates that the technology could be integrated into a portable confocal microscope for clinical applications. The
results presented here are in agreement with images obtained with the larger and more expensive femtosecond laser
system used earlier.