We describe techniques for making sensitive and high-dynamic-range measurements of laser amplitude and envelope phase noise (timing jitter) in the frequency domain at the shot-noise limit. Examples of amplitude noise measurements on continuous-wave argon-ion and diode-pumped solid-state lasers used for pumping a femtosecond Ti : sapphire laser are presented. Amplitude and phase noise measuremen...

The thermal diffusion of Ti(3+) ions into sapphire is demonstrated, and the spectroscopic characteristics of the locally doped region are presented. The spectral line shape, polarization dependence, and excited-state lifetime of indiffused Ti:sapphire are in excellent agreement with previously published data for high-quality, bulk-doped Ti:sapphire laser crystals. The observed diffusion rate at...

We report a GaN-based broadband power amplifier using AlGaN/GaN-HEMTs, grown on sapphire substrates, as the active devices. The circuit topology used novel LCRmatching networks in a 4-way binaryWilkinson combiner structure. The devices were flip-chip bonded onto the AlN circuit for thermal management. Using devices with 0.7-pm gate length and 4-mm gate width, a small-signal gain of 7 dB was obt...

Broadband 2-D multicolored arrays with more than ten periodic columns and more than ten rows were generated in a sapphire plate using two crossed femtosecond laser beams overlapping in time and space. These multicolored 2-D arrays were sensitive to rotation of the sapphire plate in the plane normal to the incident beams. The broadband spectrum, pulse duration less than 40fs, and less than 1%RMS...

We have developed a measurement head for scanning tunneling microscopy (STM) and specifically for spectroscopic imaging STM which is optimized for high mechanical stiffness and good thermal conductivity by choice of material. The main components of the microscope head are made of sapphire. Sapphire has been chosen from several competing possibilities based on finite element modeling of the fund...

We study InAs nanowire resonators fabricated on sapphire substrate with a local gate configuration. The key advantage of using an insulating sapphire substrate is that it results in a reduced parasitic capacitance, thus allowing both wide bandwidth actuation and detection using a network analyzer as well as signal detection at room temperature. Both in-plane and out-of-plane vibrational modes o...

BACKGROUND Myocardial T1-mapping recently emerged as a promising quantitative method for non-invasive tissue characterization in numerous cardiomyopathies. Commonly performed with an inversion-recovery (IR) magnetization preparation at 1.5T, the application at 3T has gained due to increased quantification precision. Alternatively, saturation-recovery (SR) T1-mapping has recently been introduced...

In organometallic vapor phase epitaxial growth of group III nitrides on sapphire, insertion of a low temperature interlayer is found to improve crystalline quality of AlxGa1-xN layer with x from 0 to 1. Here the effects of the low temperature deposited GaN or AlN interlayers on the structural quality of group III nitrides is discussed. INTRODUCTION From the late 60’s to the early 70’s Maruska a...