Confocal microscopy offers enhanced image contrast and signal-to-noise ratio compared to wide-field illumination microscopy, achieved by effectively eliminating out-of-focus background noise. In our study, we initially showcase the functionality of a line-scanning confocal microscope aligned through the utilization of a Digital Light Projector (DLP) and a rolling shutter CMOS camera. In this technique, a sequence of illumination lines is projected onto a sample using a DLP and focusing objective (50X, NA=0.55). The reflected light is imaged with the camera. Line-scanning confocal imaging is accomplished by synchronizing the illumination lines with the rolling shutter of the sensor, leading to a substantial enhancement of approximately 50% in image contrast. Subsequently, this setup is employed to create a dataset comprising 500 pairs of images of paper tissue. This dataset is employed for training a Generative Adversarial Network (cGAN). Roughly 45% contrast improvement was measured in the test images for the trained network, in comparison to the ground-truth images.
In this work, in addition to the sensor application of coated optical microresonator, we show the phase transition of Pd-H system using WGMs. WGMs are propagating on a cylindrical microresonator which is based on a single mode optical fiber coated with a desired metal thickness and desired morphology. Light coupling is achieved by tapered fiber connected to a tunable laser working in the infrared wavelength. WGMs are observed and tracked by transmitted laser light. The sensor consisting of the resonator and a tapered fiber is placed in a metal chamber that is connected to the gas tanks. Desired concentration of the gas is achieved by mixing the carrier gas (nitrogen) and hydrogen. By increasing or decreasing of the hydrogen concentration in the sensing chamber, palladium layer expands or contracts. The change in the radius of the resonator translates in to shifts in spectral positions of the WGMs. However, these expansion or contractions rates are different for different phases of the Pd – H system. For instance, solid solution of hydrogen in palladium, represented by α has the lowest expansion or contraction. In contrast β phase has the highest rate. These phase transitions and intermediate phase are shown using the WGMs.
We present a novel active fiber cavity platform for biosensing applications at 1550nm. We employed the phase shift-cavity ring down spectroscopy to the amplified fiber cavity and demonstrate sensing of sugar solutions with sensitivity and detection limit of 2659o/RIU and 1.11 × 10-5 RIU, respectively.
Fluorescence imaging of sub-cellular structures with sizes below the diffraction limit is vital in understanding cel- lular processes. Relying on exciting the sample with different illumination patterns and image processing for the elimination of background fluorescence, Structured Illumination Microscopy (SIM) provides imaging capability beyond diffraction limit using relatively simple optical setups. Here, we present a laser-free, DLP projector-based, and GPU-implemented SIM super resolution microscope. Sub-diffractive biological structures were imaged with a lateral resolution of ∼150 nm. The microscopy system is LED-based and entirely home-built which enables customizable operation at a low cost.
In this work, we present robust and easy-to-fabricate optical gas and vapor sensors based on optical fiber resonators (OFR) coated with palladium (Pd) thin films, Pd micro-particles and polymer brushes (PB). Pd based sensors are used for hydrogen (H2) gas detection in concentration range of 0% to 1% and polymer brush-coated OFR are used for detection of vapor in concentration range of 0 to 25%. Sensing mechanism of these sensors is based on spectral shift of resonance wavelength which are called whispering gallery modes (WGMs). This spectral shift is due to volume expansion of the sensing material. Tapered fiber is used in order to excite WGMs in coated OFRs. Good sensitivity and repeatability results are obtained for all three types of sensors.
We present a new method to form liquid-core optofluidic waveguides inside hydrophobic silica aerogels. Due to their
unique material properties, aerogels are very attractive for a wide variety of applications; however, it is very challenging
to process them with traditional methods such as milling, drilling, or cutting because of their fragile structure. Therefore,
there is a need to develop alternative processes for formation of complex structures within the aerogels without
damaging the material. In our study, we used focused femtosecond laser pulses for high-precision ablation of
hydrophobic silica aerogels. During the ablation, we directed the laser beam with a galvo-mirror system and,
subsequently, focused the beam through a scanning lens on the surface of bulk aerogel which was placed on a three-axis
translation stage. We succeeded in obtaining high-quality linear microchannels inside aerogel monoliths by
synchronizing the motion of the galvo-mirror scanner and the translation stage. Upon ablation, we created multimode
liquid-core optical waveguides by filling the empty channels inside low-refractive index aerogel blocks with highrefractive
index ethylene glycol. In order to demonstrate light guiding and measure optical attenuation of these
waveguides, we coupled light into the waveguides with an optical fiber and measured the intensity of transmitted light as
a function of the propagation distance inside the channel. The measured propagation losses of 9.9 dB/cm demonstrate the
potential of aerogel-based waveguides for efficient routing of light in optofluidic lightwave circuits.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.