Engineering the gain and bandwidth in avalanche photodetectors.

Avalanche and Single-Photon Avalanche photodetectors (APDs and SPADs) rely on the probability of photogenerated carriers to trigger a multiplication process. Photon penetration depth plays a vital role in this process. In silicon APDs, a significant fraction of the short visible wavelengths is absorbed close to the device surface that is typically highly doped to serve as a contact.

Scanning interferometric near-infrared spectroscopy.

In diffuse optics, quantitative assessment of the human brain is confounded by the skull and scalp. To better understand these superficial tissues, we advance interferometric near-infrared spectroscopy (iNIRS) to form images of the human superficial forehead blood flow index (BFI). We present a null source-collector (S-C) polarization splitting approach that enables galvanometer scanning and eliminates unwanted backscattered light.

Modeling of nanohole siliconphotodetectors: Steady state and transient characteristics.

Theory is proposed for nanohole silicon/photodetector (PD) physics, promising devices in the future data communications and lidar applications. Photons and carriers have wavelengths of 1m and 5 nm, respectively. We propose vertical nanoholes having 2D periodicity with a feature size of 1m will produce photons slower than those in bulk silicon, but carriers are unchanged.