LED-based photoacoustic systems have potential to diagnose diseases and tumors with high sensitivity and specificity at a cost that is affordable for all clinics. However, the expensive high-power pulsed Q-switch lasers still provide better image quality than LEDs. They also use piezoelectric transducers that are limited in sensitivity, and noise when miniaturized. Here, we present a low-cost LED-based photoacoustic imaging system with our highly sensitive optomechanical ultrasound sensor (OMUS), which is only limited by thermomechanical noise. In future, the cost of the OMUS read-out and multiplexing will enable clinical translation of in vivo small animal studies.
In this paper, we present short-wave infrared (SWIR) image sensors with high pixel density. Quantum dot (QD) photodiode stack is monolithically integrated on custom, 130 nm node CMOS readout circuit. State-of-the-art pixel pitch of 1.82 μm is demonstrated in focal plane arrays sensitive at eye-safe region above 1400 nm wavelength. Thin-film photodiode (TFPD) technology will facilitate realization of ultra-compact SWIR sensors for future XR applications, including eye-safe tracking systems and enhanced vision.
We show a proof-of-concept demonstration of a multi-parameter analysis low-cost optical detection system for the flowcytometric identification of vinegars. This multi-parameter analysis system can simultaneously measure laser induced fluorescence, absorption and scattering excited by two time-multiplexed lasers of different wavelengths. To our knowledge no other polymer optofluidic chip based system offers more simultaneous measurements. The design of the optofluidic channels is aimed at countering the effects that viscous fingering, air bubbles, and emulsion samples can have on the correct operation of such a detection system. Unpredictable variations in viscosity and refractive index of the channel content can be turned into a source of information. The sample is excited by two laser diodes that are driven by custom made low-cost laser drivers. The optofluidic chip is built to be robust and easy to handle and is reproducible using hot embossing. We show a custom optomechanical holder for the optofluidic chip that ensures correct alignment and automatic connection to the external fluidic system. We show an experiment in which 92 samples of vinegar are measured. We are able to identify 9 different kinds of vinegar with an accuracy of 94%. Thus we show an alternative approach to the classic optical spectroscopy solution at a lowered. Furthermore, we have shown the possibility of predicting the viscosity and turbidity of vinegars with a goodness-of-fit R2 over 0.947.
We present a miniaturized polymer-based micro-optical detection unit for ultraviolet and visible laser-induced fluorescence (LIF) and absorbance (ABS) analysis with an interaction length of 3 mm. We use nonsequential optical ray tracing simulations to model the system and to optimize its performance with respect to optical efficiency and system complexity. The design features a compact optical system combining total internal reflection (TIR) mirrors and refractive optics. The detection module is prototyped with deep proton writing in 2-mm-thick polymethylmethacrylate and quantitatively characterized using a three-dimensional coordinate measurement machine. We demonstrate the proof-of-concept of this TIR mirror–based module for coumarin 480 obtaining limits of detection of 50 pM and 500 nM for LIF and ABS, respectively.
In this paper we demonstrate the proof-of-concept of an optofluidic module capable of simultaneous laser-induced fluorescence (LIF) and absorbance (ABS) detection based on total internal reflection (TIR) optics. We discuss the design of the optofluidic detection module, its fabrication, and the setup used for the proof-of-concept. The injection of sample under test is done using two 3D printed syringe pumps, managing accurate injection and repeatable sample propagation through the detector module. We discuss the process of development behind these pumps and review their technical specifications. With this demonstrator setup we find that the limits of detection for the ABS and LIF detection of coumarin 480 are 500 nM and 100 nM respectively.
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