Design and Performance of Extraordinary Low-Cost Compact Terahertz Imaging System Based on Electronic Components and Paraffin Wax Optics.

Terahertz (THz) imaging is a powerful technique allowing us to explore non-conducting materials or their arrangements such as envelopes, packaging substances, and clothing materials in a nondestructive way. The direct implementation of THz imaging systems relies, on the one hand, on their convenience of use and compactness, minimized optical alignment, and low power consumption; on the other hand, an important issue remains the system cost and its figure of merit with respect to the image quality and recording parameters. In this paper, we report on the design and performance of an extraordinary low-cost THz imaging system relying on a InP Gunn diode emitter, paraffin wax optics, and commercially available GaAs high-electron-mobility transistors (HEMTs) with a gate length of 200 nm as the sensing elements in a room temperature environment.

Time resolved study of carrier relaxation dynamics in-AlO.

The relaxation of excited carriers in α-AlOis complex, depending for instance on the type of ionizing radiation. Using femtosecond time-resolved absorption spectroscopy, we can induce a controllable excitation density on a wide range, and follow the relaxation dynamics from 30 fs to 7 ns. We show that the excited carrier decay is non-exponential: it is dependent on the pump intensity, i.

Characterization of carrier behavior in photonically excited 6H silicon carbide exhibiting fast, high voltage, bulk transconductance properties.

Unabated, worldwide trends in CO production project growth to > 43-BMT per year over the next two decades. Efficient power electronics are crucial to fully realizing the CO mitigating benefits of a worldwide smart grid (~ 18% reduction for the United States alone). Even state-of-the-art SiC high voltage junction devices are inefficient because of slow transition times (~ 0.

Combined Picosecond Time-Resolved UV-Vis and NMR Techniques Used for Investigation of the Excited State Intramolecular Triplet-Triplet Energy Transfer.

The phenomenon of the intramolecular triplet-triplet (T-T) energy transfer observed for spiro[9,10-dihydro-9-oxoanthracene-10,2'-5',6'-benzindan] () molecule was investigated using stationary and time-resolved techniques in the UV/vis spectral region. The rate constant for energy transfer from anthrone chromophore to the triplet state localized on the naphthalene subunit of molecule is 2.8 × 10 s.

Lycopene crystalloids exhibit singlet exciton fission in tomatoes.

Transient absorption studies conducted on in vitro lycopene aggregates, as well as on lycopene crystalloids inside tomato chromoplasts, reveal the appearance of a long-lived excited state, which we unambiguously identified as lycopene triplet. These triplet states must be generated by singlet exciton fission, which occurs from the lycopene 2Ag state. This is the first time the singlet fission process has ever been shown to occur in a biological material.