Ultrafast Pulse Generation from Quantum Cascade Lasers.

Quantum cascade lasers (QCLs) have broken the spectral barriers of semiconductor lasers and enabled a range of applications in the mid-infrared (MIR) and terahertz (THz) regimes. However, until recently, generating ultrashort and intense pulses from QCLs has been difficult. This would be useful to study ultrafast processes in MIR and THz using the targeted wavelength-by-design properties of QCLs.

Feedback Regimes of LFI Sensors: Experimental Investigations.

In this article, we revisit the concept of optical feedback regimes in diode lasers and explore each regime experimentally from a somewhat unconventional point of view by relating the feedback regimes to the laser bias current and its optical feedback level. The results enable setting the operating conditions of the diode laser in different applications requiring operation in different feedback regimes. We experimentally explored and theoretically supported this relationship from the standard Lang and Kobayashi rate equation model for a laser diode under optical feedback.

Self-Pulsations in Terahertz Quantum Cascade Lasers under Strong Optical Feedback: The Effect of Multiple Reflections in the External Cavity.

We have recently reported the self-pulsation phenomenon under strong optical feedback in terahertz (THz) quantum cascade lasers (QCLs). One important issue, however, we left open: the effect of multiple round trips in the external cavity on the laser response to feedback. Our current analysis also casts additional light on the phenomenon of self-pulsations.

Terahertz quantum cascade laser under optical feedback: effects of laser self-pulsations on self-mixing signals.

In this article, we explore the interplay between the self-pulsations (SPs) and self-mixing (SM) signals generated in terahertz (THz) quantum cascade lasers (QCLs) under optical feedback. We find that optical feedback dynamics in a THz QCL, namely, SPs, modulate the conventional SM interference fringes in a laser feedback interferometry system. The phenomenon of fringe loss in the SM signal - well known in interband diode lasers - was also observed along with pronounced SPs.

Characterization of the complete chloroplast genome of .

The completed chloroplast genome sequence of , collected from eastern China, was firstly determined using next-generation sequencing (NGS) and bioinformatic analysis. The length of cp genome was 156,845 bp, including a large single-copy (LSC) region of 88,666 bp and a small single-copy (SSC) region of 20,543 bp, which were separated by a pair of inverted repeats (IRs) of 23,818 bp. The cp genome contained 132 genes, including 83 protein-coding genes, 41 tRNA genes, and 8 rRNA genes.

Laser feedback interferometry in multi-mode terahertz quantum cascade lasers.

The typical modal characteristics arising during laser feedback interferometry (LFI) in multi-mode terahertz (THz) quantum cascade lasers (QCLs) are investigated in this work. To this end, a set of multi-mode reduced rate equations with gain saturation for a general Fabry-Pérot multi-mode THz QCL under optical feedback is developed. Depending on gain bandwidth of the laser and optical feedback level, three different operating regimes are identified, namely a single-mode regime, a multi-mode regime, and a tuneable-mode regime.

Author Correction: Ultrafast switch-on dynamics of frequency-tuneable semiconductor lasers.

The original version of this Article contained an error in the Acknowledgements, which incorrectly omitted the following: 'We also acknowledge support from the Australian Research Council's Discovery Projects Funding Scheme (Grant DP 160 103910).' This has been corrected in both the PDF and HTML versions of the Article.

Ultrafast switch-on dynamics of frequency-tuneable semiconductor lasers.

Single-mode frequency-tuneable semiconductor lasers based on monolithic integration of multiple cavity sections are important components, widely used in optical communications, photonic integrated circuits and other optical technologies. To date, investigations of the ultrafast switching processes in such lasers, essential to reduce frequency cross-talk, have been restricted to the observation of intensity switching over nanosecond-timescales. Here, we report coherent measurements of the ultrafast switch-on dynamics, mode competition and frequency selection in a monolithic frequency-tuneable laser using coherent time-domain sampling of the laser emission.

Multi-spectral terahertz sensing: proposal for a coupled-cavity quantum cascade laser based optical feedback interferometer.

We propose a laser feedback interferometer operating at multiple terahertz (THz) frequency bands by using a pulsed coupled-cavity THz quantum cascade laser (QCL) under optical feedback. A theoretical model that contains multi-mode reduced rate equations and thermal equations is presented, which captures the interplay between electro-optical, thermal, and feedback effects. By using the self-heating effect in both active and passive cavities, self-mixing signal responses at three different THz frequency bands are predicted.

Optical sorting and cultivation of denitrifying anaerobic methane oxidation archaea.

Denitrifying anaerobic methane oxidizing (DAMO) microorganisms play an important role in the global carbon and nitrogen cycles as they are able to mediate methane oxidation using nitrite/nitrate under anoxic conditions. However, the physiological properties of DAMO microorganisms remain poorly understood, partially since the organisms are difficult to isolate or cultivate in pure culture and partially because of their long cultivation time. In this study, DAMO cell sorting has been conducted by integrating optical tweezers within enclosed microfluidic chips.

Fluorescence plasmonic enhancement of FITC labeled PS nanoparticles coupled to silver island films.

Optical properties of a fluorescence molecule can be drastically changed by surface plasmons excited in neighboring metallic nanostructures. Here we investigated the fluorescence enhancement behavior of fluorescein isothiocyanate (FITC) labeled polystyrene nanoparticles coupled to silver island films (SIFs) via a 15 nm polymethyl methacrylate separation layer theoretically and experimentally. Up to 24-fold fluorescence enhancement was experimentally achieved when the annealing time of the 25 nm Ag films was 50 min, which is in good agreement with the theoretical simulation result based on the finite-difference time-domain method.

Comparison of T-matrix calculation methods for scattering by cylinders in optical tweezers.

The T-matrix method, or the T-matrix formulation of scattering, is a framework for mathematically describing the scattering properties of an object as a linear relationship between expansion coefficients of the incident and scattering fields in a basis of vector spherical wave functions (VSWFs). A variety of methods can be used to calculate the T-matrix. We explore the applicability of the extended boundary condition method (EBCM) and point matching (PM) method to calculate the T-matrix for scattering by cylinders in optical tweezers and hence the optical force acting on them.

Development of simple sequence repeat (SSR) markers of sesame (Sesamum indicum) from a genome survey.

Sesame (Sesamum indicum), an important oil crop, is widely grown in tropical and subtropical regions. It provides part of the daily edible oil allowance for almost half of the world's population. A limited number of co-dominant markers has been developed and applied in sesame genetic diversity and germplasm identity studies.

Maternal inheritance of mitochondrial genomes and complex inheritance of chloroplast genomes in Actinidia Lind.: evidences from interspecific crosses.

The inheritance pattern of chloroplast and mitochondria is a critical determinant in studying plant phylogenetics, biogeography and hybridization. To better understand chloroplast and mitochondrial inheritance patterns in Actinidia (traditionally called kiwifruit), we performed 11 artificial interspecific crosses and studied the ploidy levels, morphology, and sequence polymorphisms of chloroplast DNA (cpDNA) and mitochondrial DNA (mtDNA) of parents and progenies. Sequence analysis showed that the mtDNA haplotypes of F1 hybrids entirely matched those of the female parents, indicating strictly maternal inheritance of Actinidia mtDNA.

Development and characterization of 59 polymorphic cDNA-SSR markers for the edible oil crop Sesamum indicum (Pedaliaceae).

Premise Of The Study: Polymorphic simple sequence repeat markers from transcript sequences (cDNA-simple sequence repeat [SSR]) were developed for the edible oil crop Sesamum indicum to facilitate the genetic study of this species. •

Methods And Results: We found 7702 SSR loci in the 60960 unigenes, and 1550 primer pairs were designed and synthesized. In total, 59 primer pairs showed polymorphism within 36 individuals; the number of alleles per locus ranged from two to four, and the expected and observed heterozygosity ranged from 0.

Characterization of the sesame (Sesamum indicum L.) global transcriptome using Illumina paired-end sequencing and development of EST-SSR markers.

Background: Sesame is an important oil crop, but limited transcriptomic and genomic data are currently available. This information is essential to clarify the fatty acid and lignan biosynthesis molecular mechanism. In addition, a shortage of sesame molecular markers limits the efficiency and accuracy of genetic breeding.

[Phylogenetic analysis and detection of selective pressure on the CVNH domains].

Cyanovirin-N (CV-N) is a novel protein with broad-spectrum antiviral activity. Its homologs constitute a protein family known as CVNH (Cyanovirin-N homology), which possess the evolutionarily conserved anti-HIV (Human immunodeficiency virus) domain. In this study, more details about the patchy organism distribution of CVNH domain were explored by reconstructing gene trees.