We introduce a novel amorphous silicon absorption filter that has high rejection for all angles of incident light for wavelengths below approximately 700 nm. This filter is used for microscopic cancer tissue detection in a small intra-operative contact fluorescence imaging system that requires excitation light at oblique angles. Our 15 mu m thick filter presents over five orders of magnitude rejection at 633 nm, making it compatible with several clinically tested fluorophores, including IR700DX. We have demonstrated imaging of fluorescently labeled human epidermal growth factor receptor 2+ breast cancer tissue using the filter, and we can reliably detect microscopic clusters of breast cancer cells with only a 75 ms integration time. (C) 2018 Optical Society of America

Present implementations of MEMS gyroscopes measure rate indirectly by first converting it to a displacement [1,2]. In this case, the scale factor is a complex function of the transducer and readout circuits. Changes of any of the underlying parameters result in measurement errors.

Cancer treatment faces the challenge of identifying small clusters of residual tumor cells in the resection cavity after the gross section of tumor is surgically removed. Despite the introduction of targeted fluorescent probes to guide cancer surgeries, large, bulky, optical components restrict the ability of fluorescence imaging devices to detect small clusters of tumor cells in the complex surgical cavity. We have developed a small size-scale contact fluorescence image sensor that incorporates angle-selective gratings and a thin 15 m amorphous silicon optical wavelength filter for detecting residual cancer tissue in vivo. Using a custom fluorescent probe combining a fluorescent dye, IR700DX, with a targeted antibody, Trastuzumab, we label and visualize breast tissue in in vivo mouse models of breast cancer. When imaging tumorbearing mice injected with the probe, HER2+ breast cancer tissue intensity is 3.80.8 times brighter than other tissue. Excised cancer tumors and residual cancer attached to healthy tissue are imaged using the custom image sensor. Residual cancer tissue can be detected in real-time and is imaged with a high SNR of 45 dB using an integration time of only 40 ms.

Microscopic tumor cell foci left in a patient after surgery significantly increase the chance of cancer recurrence. However, fluorescence microscopes used for intraoperative navigation lack the necessary sensitivity for imaging microscopic disease and are too bulky to maneuver within the resection cavity. We have developed a scalable chip-scale fluorescence contact imager for detecting microscopic cancer in vivo and in real-time. The imager has been characterized under simulated in vivo conditions using ex vivo samples, providing strong evidence that our device can be used in vivo. Angle-selective gratings enhance the resolution of the imager without impacting its physical size. We demonstrate detection of cancer cell clusters containing as few as 25 HCC1569 breast cancer cells and 400 LNCaP prostate cancer cells with integration times of only 50 ms and 70 ms, respectively. A cell cluster recognition algorithm is used to achieve both a sensitivity and specificity of 92 % for HCC1569 cell samples, indicating the reliability of the imager. The signal-to-noise ratio (SNR) degradation with increased separation is only 1.5 dB at 250 μm. Blood scattering and absorption reduce the SNR by less than 2 dB for typical concentrations. Moreover, HER2+ breast cancer tissue taken from a patient is distinguished from normal breast tissue with an integration time of only 75 ms.

Optimal cancer therapy requires targeted and individualized treatment of all tumor cells, including both gross and microscopic disease. Intraoperatively hard to visualize and often left behind, microscopic foci of residual cancer cells significantly increase the risk of cancer recurrence and treatment failure rates. Fluorescently-tagged targeted molecular labels are employed to guide surgery, but conventional fluorescent intraoperative imagers suffer from lack of sensitivity and maneuverability, limiting practicality in small tumor cavities owing to their cumbersome sizes driven by optics. This work does away with conventional lenses and filters and introduces an optics-free molecular imaging "skin" consisting of only a $25\mu \mathrm{m}$ thin CMOS contact imager that synergistically integrates the long emission lifetimes of upconverting nanoparticles (UCNP) combined with upconversion to use a time domain approach to acquire the image coupled with infrared illumination allowing deep tissue penetration and elimination of autofluorescence. Using this strategy, we are able to visualize UCNPs at fluences (W/cm2) compatible with intraoperative use, opening the door to visualize targeted areas with microscopic sensitivity and facilitate residual microscopic disease detection during surgery, and laying the groundwork for precision post-operative radiation.

Advances in minimally-invasive, distributed biological interface nodes enable possibilities for networks of sensors and actuators to connect the brain with external devices. The recent development of the neural dust sensor mote has shown that utilizing ultrasound backscatter communication enables untethered sub-mm neural recording devices. These implanted sensor motes require a wearable external ultrasound interrogation device to enable in-vivo, freely-behaving neural interface experiments. However, minimizing the complexity and size of the implanted sensors shifts the power and processing burden to the external interrogator. In this paper, we present an ultrasound backscatter interrogator that supports real-time backscatter processing in a rodent-wearable, completely wireless device. We demonstrate a generic digital encoding scheme which is intended for transmitting neural information. The system integrates a front-end ultrasonic interface ASIC with off-the-shelf components to enable a highly compact ultrasound interrogation device intended for rodent neural interface experiments but applicable to other model systems.

Modern cancer treatment faces the pervasive challenge of identifying microscopic cancer foci in vivo, but no imaging device exists with the ability to identify these cells intraoperatively, where they can be removed. We introduce a novel CMOS sensor that identifies foci of less than 200 cancer cells labeled with fluorescent biomarkers in 50ms. The sensor's miniature size enables manipulation within a small, morphologically complex, tumor cavity. Recognizing that focusing optics traditionally used in fluorescence imagers present a barrier to miniaturization, we integrate stacked CMOS metal layers above each photodiode to form angle-selective gratings, rejecting background light and deblurring the image. A high-gain capacitive transimpedance amplifier based pixel with 8.2V/s per pW sensitivity and a dark current minimization circuit enables rapid detection of microscopic clusters of 100s of tumor cells with minimal error.

An integrated electronic-photonic phase-locked loop (PLL) modulates the frequency of a tunable laser for use in frequency-modulated continuous-wave (FMCW) lidar 3D imaging. The proposed lidar can perform 180k range measurements per second. The rms depth precision is 8 μm at distances of ±5 cm from the range baseline. The range window is 1.4 m, with a precision of 4.2 mm at the edges of the window. Optical circuitry, including input light couplers, waveguides, and photodiodes, is realized on a 3 mm × 3 mm silicon-photonic chip. The 0.18-μm CMOS ASIC of the same area comprises the frontend transimpedance amplifier, analog electro-optical PLL, and digital control circuitry consuming 1.7 mA from a 1.8 V supply and 14.1 mA from a 5-V supply. The latter includes 12.5-mA bias current for the distributed Bragg reflector section of the tunable laser. The two chips are integrated using through-silicon-vias implemented in the silicon-photonic chip.

In this paper, we present a single-chip 65 ×42 element ultrasonic pulse-echo fingerprint sensor with transmit (TX) beamforming based on piezoelectric micromachined ultrasonic transducers directly bonded to a CMOS readout application-specific integrated circuit (ASIC). The readout ASIC was realized in a standard 180-nm CMOS process with a 24-V high-voltage transistor option. Pulse-echo measurements are performed column-by-column in sequence using either one column or five columns to TX the ultrasonic pulse at 20 MHz. TX beamforming is used to focus the ultrasonic beam at the imaging plane where the finger is located, increasing the ultrasonic pressure and narrowing the 3-dB beamwidth to [Formula: see text], a factor of 6.4 narrower than nonbeamformed measurements. The surface of the sensor is coated with a poly-dimethylsiloxane (PDMS) layer to provide good acoustic impedance matching to skin. Scanning laser Doppler vibrometry of the PDMS surface was used to map the ultrasonic pressure field at the imaging surface, demonstrating the expected increase in pressure, and reduction in beamwidth. Imaging experiments were conducted using both PDMS phantoms and real fingerprints. The average image contrast is increased by a factor of 1.5 when beamforming is used.

Ultrasonic fingerprint sensors based on micromachined ultrasound transducers require very fine pitch to achieve high resolution imaging. We investigate a 110×56 PMUT array based on monolithic eutectic bonding to CMOS. To achieve high fill-factor, the PMUTs are anchored through small eutectic pillars, resulting in a high degree of mutual coupling between neighboring PMUTs. As a result, the mode shape is more complicated than a single-MUT dynamic model. We created a finite element model that better models the mode shapes exhibited by the entire array. Experimental measurement of the mode-shape via laser Doppler vibrometry allows us to compute the volume velocity, which correlates to the measured far field pressure.

3D imaging technologies are applied in numerous areas, including self-driving cars, drones, and robots, and in advanced industrial, medical, scientific, and consumer applications. 3D imaging is usually accomplished by finding the distance to multiple points on an object or in a scene, and then creating a point cloud of those range measurements. Different methods can be used for the ranging. Some of these methods, such as stereovision, rely on processing 2D images. Other techniques estimate the distance more directly by measuring the round-trip delay of an ultrasonic or electromagnetic wave to the object. Ultrasonic waves suffer large losses in air and cannot reach distances beyond a few meters. Radars and lidars use electromagnetic waves in radio and optical spectra, respectively. The shorter wavelengths of the optical waves compared to the radio frequency waves translates into better resolution, and a more favorable choice for 3D imaging. The integration of lidars on electronic and photonic chips can lower their cost, size, and power consumption, making them affordable and accessible to all the abovementioned applications. This review article explains different lidar aspects and design choices, such as optical modulation and detection techniques, and point cloud generation by means of beam-steering or flashing an entire scene. Popular lidar architectures and circuits are presented, and the superiority of the FMCW lidar is discussed in terms of range resolution, receiver sensitivity, and compatibility with emerging technologies. At the end, an electronic-photonic integrated circuit for a micro-imaging FMCW lidar is presented as an example.

This paper presents a 591×438-DPI ultrasonic fingerprint sensor. The sensor is based on a piezoelectric micromachined ultrasonic transducer (PMUT) array that is bonded at wafer-level to complementary metal oxide semiconductor (CMOS) signal processing electronics to produce a pulse-echo ultrasonic imager on a chip. To meet the 500-DPI standard for consumer fingerprint sensors, the PMUT pitch was reduced by approximately a factor of two relative to an earlier design. We conducted a systematic design study of the individual PMUT and array to achieve this scaling while maintaining a high fill-factor. The resulting 110×56-PMUT array, composed of 30×43-μm 2 rectangular PMUTs, achieved a 51.7% fill-factor, three times greater than that of the previous design. Together with the custom CMOS ASIC, the sensor achieves 2 mV kPa −1 sensitivity, 15 kPa pressure output, 75 μm lateral resolution, and 150 μm axial resolution in a 4.6 mm×3.2 mm image. To the best of our knowledge, we have demonstrated the first MEMS ultrasonic fingerprint sensor capable of imaging epidermis and sub-surface layer fingerprints.

Development of microfabricated imagers placed within the resection bed intraoperatively can significantly improve image-guided surgery. One application is identifying microscopic disease during cancer removal. This class of imagers requires robustness against variations in fluid, blood, and tissue surface profile which vary the distance of the tissue from the imager, causing light from the sample to be incident on the imager at a wide range of angles, thereby blurring the image. This paper addresses this problem by demonstrating an angle-selective imager fabricated in a 0.18um CMOS process, capable of reducing light incident at angles >25° from the perpendicular by >50%.

This paper presents a 591×438 DPI ultrasonic fingerprint sensor. The sensor is based on a piezoelectric micromachined ultrasonic transducer (PMUT) array that is bonded at wafer-level to complementary metal oxide semiconductor (CMOS) signal processing electronics to produce a pulse-echo ultrasonic imager on a chip. To meet the 500 DPI standard for consumer fingerprint sensors, the PMUT pitch was reduced by approximately a factor of two relative to an earlier design. We conducted a systematic design study of the individual PMUT and array to achieve this scaling while maintaining a high fill-factor. The resulting 110×56 PMUT array, composed of 30×43μm2 rectangular PMUTs achieved a 51.7% fill-factor, three times greater than that of the previous design. Together with the custom CMOS ASIC, the sensor achieves 2 μV/Pa sensitivity, 13 kPa pressure output, 75μm lateral resolution, and 150μm axial resolution in a 4.6 mm × 3.2 mm image.

This paper describes air-coupled piezoelectric micromachined ultrasonic transducers (PMUTs) for consumer electronics applications including time-of-flight range-finding, proximity and presence sensing, and gesture recognition. These applications require sensors that are small size, low-cost, and ultra-low-power, all of which are characteristics of PMUTs.