Optical microscopy is one of the most widely used diagnostic methods in scientific, industrial, and biomedical applications. However, while useful for detailed examination of a small number (< 10,000) of microscopic entities, conventional optical microscopy is incapable of statistically relevant screening of large populations (> 100,000,000) with high precision due to its low throughput and limited digital memory size. We present an automated flow-through single-particle optical microscope that overcomes this limitation by performing sensitive blur-free image acquisition and nonstop real-time image-recording and classification of microparticles during high-speed flow. This is made possible by integrating ultrafast optical imaging technology, self-focusing microfluidic technology, optoelectronic communication technology, and information technology. To show the system’s utility, we demonstrate high-throughput image-based screening of budding yeast and rare breast cancer cells in blood with an unprecedented throughput of 100,000 particles/s and a record false positive rate of one in a million.

D etermining the instantaneous frequency of a signal is required for many applications ranging from radio astronomy to defense applications. Unfortunately, the scan rate is often too long over a wideband spectrum compared to the time scale of signals of interest. We present an instantaneous frequency measurement receiver, which allows for simultaneous measurement of multiple frequencies and amplitudes across an ultra-wide instantaneous bandwidth. Powered by the photonic time stretch A/D converter, the high effective sampling throughput of the system provides high temporal resolution and improvement of frequency and amplitude estimation capability through advanced signal processing. This flexible system has adjustable instantaneous bandwidth and frequency resolution, an ultrafast sweep time, and reduced hardware complexity compared to other instantaneous frequency measurement systems. Instantaneous Frequency Measurement ReceiversThe instantaneous frequency measurement (IFM) receiver has been an increasingly important tool for measuring radiofrequency (RF) signals over a wide bandwidth. It is used to measure RF frequency, amplitude, pulse width, and time of arrival for a plethora of applications such as radar threat detection, electronic warfare, and signal intelligence [1]. A wideband IFM receiver offers a high probability of intercept over wide instantaneous RF bandwidths, large dynamic ranges, good sensitivity and high frequency measurement accuracy. Currently, IFM receivers are limited in performance mainly by their ability to measure only single frequencies at a time, having limited bandwidths, and slow sweep times across enormous bandwidths. Additional channels would be required to expand the bandwidth which would increase the hardware complexity. The time-stretch instantaneous frequency measurement receiver (TS-IFM) is able to overcome these challenges and provide a solution capable of ultra-fast sweeping across enormous bandwidths to perform measurements on transient signals. In today's spectrally cluttered environments, we need a system that can perform measurements across wider bandwidths and detect frequencies of interest quickly and efficiently. Current IFM MethodsTraditional IFMs use microwave interferometers and make use of hybrid couplers, power dividers, and delay lines to perform measurements. The basic measurement technology consists of a microwave correlator to measure an unknown signal. A traditional IFM will split the incoming signal into two paths and delay one path by a time t with respect to the other along with a 90-degree phase shift. Subsequently, the ratio of the two paths is taken and an arc tangent operation is performed to determine the input frequency of the received signal.A limitation of using this method is that it can measure only a single frequency at a time, and measuring amplitude requires another set of discriminators. While there may be other signals in the band, the IFM receiver measures only the largest RF signal in the band [1]. Moreover, the largest signal must also be s...

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A new instrument for fast measurement of frequency response of high-bandwidth optical and electronic devices is reported. Single-shot frequency spectrum measurements are enabled by time-stretch technology. An extremely fast measurement time of 27 ns is reported for the instrument. The reported instrument enables single-shot impulse response measurements with a 40 GHz bandwidth, which could be extended to beyond 100 GHz by using a faster electro-optic modulator. An ultra-low jitter of 20.5 fs is reported for the proposed instrument. The impulse responses measured using this technique are shown to correspond consistently with the manufacturer's specifications for the device under test. The reported instrument makes possible high-speed network parameter measurements, thereby enabling high-speed production-level testing of high-bandwidth opto-electronic devices/circuits/subsystems/systems and complex permittivity measurement of dielectric materials at a much reduced test time, lowering the test costs in a production environment.