Baolei Liu

Beihang University | BUAA ·  Department of Physics

Miniaturized on-chip spectrometers with small footprints, lightweight, and low cost are in great demand for portable optical sensing, lab-on-chip systems, and so on. Such miniaturized spectrometers are usually based on engineered spectral response units and then reconstruct unknown spectra with algorithms. However, due to the limited footprints of...

Super‐resolution fluorescence microscopy is of great interest in life science studies for visualizing subcellular structures at the nanometer scale. Among various kinds of super‐resolution approaches, image scanning microscopy (ISM) offers a doubled resolution enhancement in a simple and straightforward manner, based on the commonly used confocal m...

Precise force measurement is critical to probe biological events and physics processes, spanning from molecular motor’s motion to the Casimir effect, as well as the detection of gravitational waves. Yet, despite extensive technological developments, the three-dimensional nanoscale measurement of weak forces in aqueous solutions still faces major ch...

Lensless imagers based on diffusers or encoding masks enable high-dimensional imaging from a single-shot measurement and have been applied in various applications. However, to further extract image information such as edge detection, conventional post-processing filtering operations are needed after the reconstruction of the original object images...

Miniaturized on-chip spectrometers with small footprints, lightweight, and low cost are in great demand for portable optical sensing, lab-on-chip systems, and so on. Such miniaturized spectrometers are usually based on engineered spectral response units and then reconstruct unknown spectra with algorithms. However, due to the limited footprints of...

Ultraviolet (UV) imaging enables a diverse array of applications, such as material composition analysis, biological fluorescence imaging, and detecting defects in semiconductor manufacturing. However, scientific-grade UV cameras with high quantum efficiency are expensive and include complex thermoelectric cooling systems. Here, we demonstrate a UV...

Lensless diffuser camera is a novel and flexible approach to capture object’s images. Here, we propose a compact spectral and polarization diffuser camera (SPDC) enabled by a diffuser and a complementary metal oxide semiconductor (COMS) sensor. We demonstrated SPDC to reconstruct images with spectral and polarization by simulations. It can be highl...

Miniature spectrometers are in high demand for portable optical sensing, on-chip systems, and other consumer applications, due to their small size and light weight. Recently, on-chip spectrometers, which are based on simple hardware systems, and recover unknown spectra by reconstruction algorithms, have become one of the most important research tre...

Super-resolution microscopy provides a high spatial resolution that is beyond the diffraction barrier and can visualize nano-sized structures and interactions in biological and material study. In recent years, lanthanide-doped upconversion nanoparticles (UCNPs) that can upconvert the near-infrared (NIR) excitation photons to visible emission photon...

Optical multiplexing for nanoscale object recognition is of great significance within the intricate domains of biology, medicine, anti‐counterfeiting and microscopic imaging. Traditionally, the multiplexing dimensions of nanoscopy are limited to emission intensity, colour, lifetime, and polarization. Here we propose a novel dimension, optical nonli...

Lensless imagers based on diffusers or encoding masks enable high-dimensional imaging from a single shot measurement and have been applied in various applications. However, to further extract image information such as edge detection, conventional post-processing filtering operations are needed after the reconstruction of the original object images...

Ultraviolet (UV) imaging enables a diverse array of applications, such as material composition analysis, biological fluorescence imaging, and detecting defects in semiconductor manufacturing. However, scientific-grade UV cameras with high quantum efficiency are expensive and include a complex thermoelectric cooling system. Here, we demonstrate a UV...

Manufacturing sharp features is one of the most desired requirements for lithography. Here, we demonstrate a dual-path self-aligned polarization interference lithography (Dp-SAP IL) for fabricating periodic nanostructures, featuring high-steepness and high-uniformization. Meanwhile, it can manufacture quasicrystals with adjustable rotation symmetry...

In this paper, we present a dual-mode adaptive singular value decomposition ghost imaging (A-SVD GI), which can be easily switched between the modes of imaging and edge detection. It can adaptively localize the foreground pixels via a threshold selection method. Then only the foreground region is illuminated by the singular value decomposition (SVD...

In this paper, we present a dual-mode adaptive singular value decomposition ghost imaging (A-SVD GI), which can be easily switched between the modes of imaging and edge detection. It can adaptively localize the foreground pixels via a threshold selection method. Then only the foreground region is illuminated by the singular value decomposition (SVD...

In this paper, we present a dual-mode adaptive singular value decomposition ghost imaging (A-SVD GI), which can be easily switched between the modes of imaging and edge detection. It can adaptively localize the foreground pixels via a threshold selection method. Then only the foreground region is illuminated by the singular value decomposition (SVD...

Quantifying the size range of aerosols that can be trapped in a counterpropagation dual-fiber trapping configuration is important in understanding how these particles can be manipulated and characterized in such traps. Here, we present simulations and experiments investigating the trapped aerosol size range variations in the intermediate position o...

Interferometric Scattering Microscopy Rayleigh scattering of the nanoparticles can be engineered by doping lanthanide ions, which is based on the enhanced polarizability of the nanoparticles when the excitation wavelength matches the ion resonance frequency of the lanthanide ions. More details can be found in article number 2203354 by Baolei Liu, C...

Precise force measurement is critical to probing biological events and physics processes, spanning from molecular motor’s motion to the Casimir effect ¹ and the detection of gravitational wave ² . Yet, despite extensive technology developments, the 3D nanoscale measurement of weak forces in aqueous solutions poses a significant challenge. Technique...

Single-beam super-resolution microscopy, also known as superlinear microscopy, exploits the nonlinear response of fluorescent probes in confocal microscopy. The technique requires no complex purpose-built system, light field modulation, or beam shaping. Here, we present a strategy to enhance this technique's spatial resolution by modulating excitat...

Light scattering from nanoparticles is significant in nanoscale imaging, photon confinement. and biosensing. However, engineering the scattering spectrum, traditionally by modifying the geometric feature of particles, requires synthesis and fabrication with nanometre accuracy. Here it is reported that doping lanthanide ions can engineer the scatter...

Single-beam super-resolution microscopy, also known as superlinear microscopy, exploits the nonlinear response of fluorescent probes in confocal microscopy. The technique requires no complex purpose-built system, light field modulation, or beam shaping. Here, we present a strategy to enhance spatial resolution of superlinear microscopy by modulatin...

The emerging optical multiplexing within nanoscale shows super-capacity in encoding information by using lifetime fingerprints from luminescent nanoparticles. However, the optical diffraction limit compromises the decoding accuracy and throughput of the nanoparticles during conventional widefield imaging. This, in turn, challenges the quality of na...

Highly controlled synthesis of upconversion nanoparticles (UCNPs) can be achieved in the heterogeneous design, so that a library of optical properties can be arbitrarily produced from each batch of synthesis, based on the depositions of multiple lanthanide ions. Such a control offers the potential in creating nanoscale barcodes carrying high-capaci...

Ghost imaging captures 2D images with a point detector instead of an array sensor. It could therefore solve the challenge of building cameras in wave bands where sensors are difficult and expensive to produce and could open up more routine THz, near-infrared, lifetime, and hyperspectral imaging simply by using single-pixel detectors. Traditionally,...

We present a compact, diffuser assisted, single-pixel computational camera. A rotating ground glass diffuser is adopted, in preference to a commonly used digital micro-mirror device (DMD), to encode a two-dimensional (2D) image into single-pixel signals. We retrieve images with an 8.8% sampling ratio after the calibration of the pseudo-random patte...

The control in optical uniformity of single nanoparticles and tuning their diversity in multiple dimensions, dot to dot, holds the key to unlocking nanoscale applications. Here we report that the entire lifetime profile of the single upconversion nanoparticle (τ2 profile) can be resolved by confocal, wide-field, and super-resolution microscopy tech...

The diverse photoresponses from different energy levels in lanthanide‐doped nanoparticles enables simultaneous generation of multiple point‐spread functions with one doughnut‐shaped excitation beam. In article number 2008847, Fan Wang, Dayong Jin, and co‐workers explore a new imaging modality to extend the capabilities of the engineered point‐sprea...

We present a compact, diffuser-assisted, single-pixel computational camera. A rotating ground glass diffuser is adopted, in preference to a commonly used digital micro-mirror device (DMD), to encode a two-dimensional (2D) image into single-pixel signals. We retrieve images with an 8.8% sampling ratio after the calibration of the pseudo-random patte...

Point spread function (PSF) engineering by an emitter's response can code higher‐spatial‐frequency information of an image for microscopy to achieve super‐resolution. However, complexed excitation optics or repetitive scans are needed, which explains the issues of low speed, poor stability, and operational complexity associated with the current las...

The emerging optical multiplexing within nanoscale shows super-capacity in encoding information by using the time-domain fingerprints from uniform nanoparticles. However, the optical diffraction limit compromises the decoding throughput and accuracy of the nanoparticles during wide-field imaging. This, in turn, challenges the quality of nanoparticl...

Point spread function (PSF) engineering by emitter's response can code higher spatial frequency information of an image for microscopy to achieve super-resolution. However, complexed excitation optics or repetitive scans are needed, which explains the issues of low speed, poor stability and operational complexity associated with the current laser s...

The control in optical uniformity of single nanoparticles and tuning their diversity in orthogonal dimensions, dot to dot, holds the key to unlock nanoscience and applications. Here we report that the time-domain emissive profile from single upconversion nanoparticle, including the rising, decay and peak moment of the excited state population (T2 p...

Ghost imaging can capture 2D images with a point detector instead of an array sensor. It therefore offers a solution to the challenge of building area format sensors in wavebands where such sensors are difficult and expensive to produce and opens up new imaging modalities due to high-performance single-pixel detectors. Traditionally, ghost imaging...

To simplify the reconstruction algorithms in ghost imaging, we present a feedback-based approach to reduce reconstruction times. We introduce a genetic algorithm to optimize the illumination patterns in real-time to match with the object's shape.

A terahertz (THz) reflect-array is proposed. Dual circularly polarized (left-and right-hand-circular-polarizations) collimated beams are independently manipulated. In our model, the left-hand-circularly-polarized and right-hand-circularly-polarized beams reflect at 23-degrees along the y-direction and x-direction respectively. © 2020 The Author(s)...

Correction for ‘Video-rate upconversion display from optimized lanthanide ion doped upconversion nanoparticles’ by Laixu Gao et al. , Nanoscale , 2020, DOI: 10.1039/d0nr03076g.

We developed a video-rate upconverting display system with much enhanced brightness. The integral emission intensity of the single Volumetric displays that create bright image points within a transparent bulk is one of the most attracting technologies in everyday life. Lanthanide ions doped upconversion nanoparticles (UCNPs) is an promising lumines...

Video-rate super-resolution imaging through biological tissue can visualize and track biomolecule interplays and transportations inside cellular organisms. Structured illumination microscopy allows for wide-field super resolution observation of biological samples but is limited by the strong extinction of light by biological tissues, which restrict...

Video-rate super-resolution imaging through biological tissue can visualize and track biomolecule interplays and transportations inside cellular organisms. Structured illumination microscopy allows for wide-field super resolution observation of biological samples but is limited by the strong absorption and scattering of light by biological tissues,...

An approach for improving ghost imaging (GI) quality is proposed. In this paper, an iteration model based on normalized GI is built through theoretical analysis. An adaptive threshold value is selected in the iteration model. The initial value of the iteration model is estimated as a step to remove the correlated noise. The simulation and experimen...

The invention discloses a single-optical arm correlation imaging method for compensating atmospheric turbulence. The method includes the following steps that: an atmospheric turbulence phase screen Phi (m,n) is constructed; the measurement matrix A of a spatial modulator is compensated according to the Phi (m,n), so that a compensated measurement m...

In traditional direct imaging a scattering medium between the object and detection system will severely degrade the image quality. Computational correlation imaging (GI) has a unique advantage in that the effect of the light scattering can be greatly reduced. We present an analysis of computational correlation imaging and traditional direct imaging...

We propose and demonstrate a computational imaging technique that uses structured illumination based on a two-dimensional discrete cosine transform to perform imaging with a single-pixel detector. A scene is illuminated by a projector with two sets of orthogonal patterns, then by applying an inverse cosine transform to the spectra obtained from the...

The present invention provides a single-pixel rapid active imaging system based on discrete cosine transform, which can be used for carrying out high-quality imaging. The technical core of the single-pixel rapid active imaging system is two-dimensional cosine orthorhombic structure light fields based on two-dimensional discrete cosine transform, wh...

The utility model discloses a polarized interference type fully distributed double-parameter optical fiber sensor, which is characterized in that the sensor comprises: a laser-polarizer P1-beam splitter 1-circulator C1-side hole optical fiber-circulator C2-check The polarizer P2-combiner 1-detector PD1, the above components are sequentially connect...