Yi-Shan Lee

National Central University | NCU · Department of Electrical Engineering

Photon-number-resolving detectors are in high demand for applications in photonic quantum technology. In this study, we demonstrate the photon-number-resolving capabilities of our self-developed, highly efficient InGaAs/InAlAs single-photon avalanche diode. We achieved intrinsic photon number resolving by harnessing the high multiplication gain gen...

Multiple multiplication-layers SPADs with excellent performances in terms of high-efficiency (>74%), neat impulse response time (101ps), and short hold-off time (83ns@<1% afterpulsing) can be achieved simultaneously with a simple passive quenching circuit under gated-mode operations.

We demonstrate a novel avalanche photodiode (APD) design which fundamentally relaxes the trade-off between responsivity and saturation-current performance at receiver end in coherent system. Our triple In0.52Al0.48As based multiplication (M-) layers with a stepped electric (E-) field inside has more pronounced avalanche process with significantly l...

We carry out an In0.53Ga0.47As/In0.52Al0.48As single photon avalanche diode which exhibits a single photon detection efficiency exceeding 60% at 1310 nm and neat temporal characteristic of 65 ps. A novel concept of dual multiplication layer is incorporated to compromise the dark count rate, afterpulsing and timing jitter, paving the possibility to...

In this work, we demonstrate the high-power and high-responsivity performance of the dual multiplication (M-) layers in In0.52 Al0.48 As based avalanche photodiode (APD). The dual M-layer design in our APD structure effectively constrains the multiplication process to a thin high-field region rather than the whole thick M-layer. It thus minimizes t...

In this work, we demonstrate In0.52Al0.48As top/backside-illuminated avalanche photodiodes (APD) with dual multiplication layers for high-speed and wide dynamic range performances. Our fabricated top-illuminated APDs, with a partially depleted p-type In0.53Ga0.47As absorber layer and thin In0.52Al0.48As dual multiplication (M-) layer (60 and 88 nm)...

In this work, we demonstrate a novel In0.52Al0.48As based top-illuminated avalanche photodiode (APD), designed to circumvent the problem of serious bandwidth degradation under high gain (>100) and high power operation and significantly enhance the dynamic range in the established frequency modulated continuous wave (FMCW) lidar system. In our APD d...

The performance of InGaAs/InAlAs single photon avalanche diodes (SPAD) was improved with fabrication in triple mesa. Current SPADs achieve better dark count rate of 5 × 104 ⁄2 for single photon detection efficiency of 31% at RT.

Dual multiplication-layers APDs with large bandwidth-responsivity product (460GHz-A/W), saturation-current (>10mA), and IF-power (+4.5dBm) are demonstrated in self-heterodyne FWCW lidar systems with ~285% modulation depths. Constructed images show 9.5dB larger SNRs than that of p-i-n PD.

Macroscopic coherence of Bose condensates is a fundamental and practical phenomenon in many-body systems, such as the long-range correlation of exciton-polariton condensates with a dipole density typically below the exciton Mott-transition limit. Here we extend the macroscopic coherence of electron-hole-photon interacting systems to a new region in...

Coupled electron-hole-photon systems in semiconductor microcavities have been a platform for studies of laser dynamics and nonequilibrium cooperative phenomena in solid states. Here, we report the observation of multiple-pulse lasing in optically induced confinement in a highly photoexcited semiconductor microcavity at room temperature. The spatial...

We demonstrate sequential lasing at two well-separated energies in a highly photoexcited planar microcavity at room temperature. Two spatially overlapped lasing states with distinct polarization properties appear at energies more than 5 meV apart. Under a circularly polarized nonresonant 2 ps pulse excitation, a sub-10-ps transient circularly polar...

We propose and demonstrate a new method for evaluating the afterpulsing effect in single-photon avalanche photodiodes (SPADs). By analyzing the statistical property of dark count rate, we can quantitatively characterize afterpulsing probability (APP) of a SPAD. In experiment, the temperature-dependent low dark count rate (DCR) distribution becomes...

We demonstrate room-temperature spin-polarized ultrafast ($\sim$10 ps) lasing in a highly optically excited GaAs microcavity. This microcavity is embedded with InGaAs multiple quantum wells in which the spin relaxation time is less than 10 ps. The laser radiation remains highly circularly polarized even when excited by nonresonant elliptically pola...

We demonstrate highly circularly polarized lasing under non-resonant elliptically polarized optical pumping in a semiconductor microcavity at room temperature.

We demonstrate a dynamic macroscopic quantum oscillator of cavity-induced correlated electron-hole pairs in high-density plasmas created in an optically induced confining potential in a semiconductor microcavity at room temperature. One major advancement is the visualization of quantum oscillator states in a micrometer-scale optical potential at qu...

We present an experimental study of the influence of incoherent pumping upon the strong coupling between quantum dot excitons and a micropillar-cavity. For two exchange-split excitons, the inherent difference in the detuning with respect to the cavity modes leads to an unequal reduction of Rabi splitting for two orthogonal polarizations as excitati...

We report room-temperature sequential polariton lasing at two distinct energies in a planar microcavity non-resonantly pumped by a 2-ps pulsed laser. The sample consists of multiple InGaAs/GaAs quantum wells embedded within GaAs/AlGaAs distributed Bragg mirrors. A sub-10-ps high energy (HE) lasing mode with a linewidth ∼ 3 meV commences within 10 p...

A high-quality planar two-dimensional p-i-n light emitting diode in an entirely undoped GaAs/AlGaAs quantum well has been fabricated by using conventional lithography process. With twin gate design, two-dimensional electron and hold gases can be placed closely on demand. The electroluminescence of the device exhibit high stability and clear transit...

We study the polarization properties of quantum dot (QD) emission coupled with the fundamental cavity modes. A rotation of polarization axis and a change of polarization degree are observed as the coupling is varied. To explain this observation, we derive an analytical model considering the polarization misalignment between QD dipole and cavity mod...

We introduce a method for designing an H1 photonic crystal cavity to enhance its quality factor ( Q factor). The highest theoretical Q factor of 120,000 is obtained. The Fourier transformation of field distribution shows that the enhancement arises from the component reduction of a leaky mode. The Q -factor improvement has also been demonstrated ex...

Light-matter interactions are greatly altered in resonators and heterostructures where both electrons and photons are confined. These interactions lead to nonlinear optical processes and lasing where both photon mode control and electron quantum confinement play a role. Lasing in semiconductors is generally independent of the spins of electrons and...

We propose and demonstrate a novel device structure of resonant cavity-enhanced photodetector (RCE-PD). The new RCE-PD structure consists of a bottom distributed Bragg reflector (DBR), a cavity with InGaAs multiple quantum wells (MQWs) for light absorption and a top mirror of sub-wavelength grating. By changing the fill factor of the 2-D grating, t...

We present the control of couplings between quantum dots and cavity modes in microdisk microcavities by a stress tuning scheme. The excitonic transitions and cavity modes can be brought into resonance due to their different energy shift rates with the applied strain. Spectral signatures of both strong and weak couplings are clearly observed. The st...