Ultra-high-Q microcavity operation in H2O and D2O

Optical microcavities provide a possible method for boosting the detection sensitivity of biomolecules. Silica-based microcavities are important because they are readily functionalized, which enables unlabeled detection. While silica resonators have been characterized in air, nearly all molecular detections are performed in solution. Therefore, it is important to determine their performance limits in an aqueous environment. In this letter, planar microtoroid resonators are used to measure the relationship between quality factor and toroid diameter at wavelengths ranging from visible to near-IR in both H2O and D2O, and results are then compared to predictions of a numerical model. Quality factors (Q) in excess of 10^8, a factor of 100 higher than previous measurements in an aqueous environment, are observed in both H2O and D2O

Ultra-high-Q toroid microcavities on a chip

We demonstrate microfabrication of ultra-high-Q microcavities on a chip, exhibiting a novel toroid-shaped geometry. The cavities possess Q-factors in excess of 100 million which constitutes an improvement close to 4 orders-of-magnitude in Q compared to previous work [B. Gayral, et al., 1999]

Fabrication and coupling to planar high-Q silica disk microcavities

Using standard lithographic techniques, we demonstrate fabrication of silica disk microcavities, which exhibit whispering-gallery-type modes having quality factors (Q) in excess of 1 million. Efficient coupling (high extinction at critical coupling and low, nonresonant insertion loss) to and from the disk structure is achieved by the use of tapered optical fibers. The observed high Q is attributed to the wedged-shaped edge of the disk microcavity, which is believed to isolate modes from the disk perimeter and thereby reduce scattering loss. The mode spectrum is measured and the influence of planar confinement on the mode structure is investigated. We analyze the use of these resonators for very low loss devices, such as add/drop filters

Ultralow-threshold microcavity Raman laser on a microelectronic chip

Using ultrahigh-Q toroid microcavities on a chip, we demonstrate a monolithic microcavity Raman laser. Cavity photon lifetimes in excess of 100 ns combined with mode volumes typically of less than 1000 µm^3 significantly reduce the threshold for stimulated Raman scattering. In conjunction with the high ideality of a tapered optical fiber coupling junction, stimulated Raman lasing is observed at an ultralow threshold (as low as 74 µW of fiber-launched power at 1550 nm) with high efficiency (up to 45% at the critical coupling point) in good agreement with theoretical modeling. Equally important, the wafer-scale nature of these devices should permit integration with other photonic, mechanical, or electrical functionality on a chip

Recent progress on the accurate determination of the equation of state of neutron and nuclear matter

The problem of accurately determining the equation of state of nuclear and neutron matter at density near and beyond saturation is still an open challenge. In this paper we will review the most recent progress made by means of Quantum Monte Carlo calculations, which are at present the only ab-inito method capable to treat a sufficiently large number of particles to give meaningful estimates depending only on the choice of the nucleon-nucleon interaction. In particular, we will discuss the introduction of density-dependent interactions, the study of the temperature dependence of the equation of state, and the possibility of accurately studying the effect of the onset of hyperons by developing an accurate hyperon-nucleon and hyperon-nucleon-nucleon interaction.Comment: 3 figures, 1 table, to appear in the Proceedings of "XIII Convegno di Cortona su Problemi di Fisica Nucleare Teorica", Cortona (Italy), April 6-8, 201

PERANCANGAN WATER METHANOL INJECTION UNTUK MESIN HONDA K24Z2 MENGGUNAKAN ARDUINO

WMI (Water Methanol Injection) adalah sebuah alat yang berfungsi untuk menginjeksikan campuran air dan metanol kedalam ruang bakar sebuah mesin pembakaran dalam. Water Methanol Injection tidak bekerja untuk menggantikan sistem injeksi bahan bakar suatu mesin, tetapi bekerja secara berdampingan untuk meningkatkan efisiensi output yang dihasilkan mesin tersebut. Faktanya metanol memiliki nilai oktan yang tinggi, sehingga dengan menginjeksikan berdampingan dengan bahan bakar akan menghasilkan mesin yang lebih bertenaga dan irit bahan bakar. Dengan menggunakan prinsip injeksi sebagai metoda untuk memasukan methanol dan air kedalam mesin. Maka diperlukan suatu sistem yang mampu mengatur tekanan, debit, dan pulsa injeksi untuk menjaga alat tersebut tetap optimal. Menggunakan alat mekanis seperti pompa DC, selang, dan nosel yang bekerja untuk menginjeksikan campuran air dan methanol kedalam ruang bakar. Kemudian alat tersebut akan dikontrol oleh algoritma pada sebuah mikrokontroler. Dengan menambahkan WMI maka diharapkan performa mesin akan meningkat sebesar 5%. Kemudian dengan penambahan mikrokontroler diharapkan Water Methanol Injection lebih stabil, dan presisi saat menginjeksikan air dan methanol tersebut sesuai dengan pengaturan. Kata kunci: WMI, injeksi, kontrole

Exploring the role of skeletal muscle in insulin resistance: lessons from cultured cells to animal models

Skeletal muscle is essential to maintain vital functions such as movement, breathing, and thermogenesis, and it is now recognized as an endocrine organ. Muscles release factors named my-okines, which can regulate several physiological processes. Moreover, skeletal muscle is particularly important in maintaining body homeostasis, since it is responsible for more than 75% of all insulin-mediated glucose disposal. Alterations of skeletal muscle differentiation and function, with subse-quent dysfunctional expression and secretion of myokines, play a key role in the pathogenesis of obesity, type 2 diabetes, and other metabolic diseases, finally leading to cardiometabolic complica-tions. Hence, a deeper understanding of the molecular mechanisms regulating skeletal muscle function related to energy metabolism is critical for novel strategies to treat and prevent insulin resistance and its cardiometabolic complications. This review will be focused on both cellular and animal models currently available for exploring skeletal muscle metabolism and endocrine func-tion

High sensitivity nanoparticle detection using optical microcavities

We demonstrate a highly sensitive nanoparticle and virus detection method by using a thermal-stabilized reference interferometer in conjunction with an ultrahigh-Q microcavity. Sensitivity is sufficient to resolve shifts caused by binding of individual nanobeads in solution down to a record radius of 12.5 nm, a size approaching that of single protein molecules. A histogram of wavelength shift versus nanoparticle radius shows that particle size can be inferred from shift maxima. Additionally, the signal-to-noise ratio for detection of Influenza A virus is enhanced to 38:1 from the previously reported 3:1. The method does not use feedback stabilization of the probe laser. It is also observed that the conjunction of particle-induced backscatter and optical-path-induced shifts can be used to enhance detection signal-to-noise