Richard Forber

Electro-optic sensor from high Q resonance between optical D-fiber and slab waveguide.

An electric-field sensor is specially fabricated with an optical D-fiber that utilizes weak evanescent coupling with a lithium niobate slab waveguide. Resonant modes with a Q-factor of ~13,000 yield high sensitivity for detecting electric fields.

Electric-field sensors utilizing coupling between a D-fiber and an electro-optic polymer slab.

This paper provides a detailed analysis of electric field sensing using a slab-coupled optical fiber sensor (SCOS). This analysis explains that the best material for the slab waveguide is an inorganic material because of the low RF permittivity combined with the high electro-optic coefficient. The paper also describes the fabrication and testing of a SCOS using an AJL chromophore in amorphous polycarbonate. The high uniform polymer slab waveguide is fabricated using a hot embossing process to create a slab with a thickness of 50 μm. The fabricated polymer SCOS was characterized to have a resonance slope of ΔP/Δλ=6.83E5 W/m and a resonance shift of Δλ/E=1.47E-16 m(2)/V.

Electric field sensing with a hybrid polymer/glass fiber

We demonstrate the operation of an in-fiber electric field sensor. The sensor is fabricated with selective chemical etching of the core of a D-shaped optical fiber followed by the deposition of an electro-optic polymer (PMMA/DR1), which forms a hybrid core. The device demonstrates electromagnetic field sensitivity less than 100 V/m at a frequency of 2.9 GHz. Epi is estimated to be 60 MV/m with an insertion loss of 14.4 dB.

Multiaxis electric field sensing using slab coupled optical sensors

This paper provides the details of a multiaxis electric field sensor. The sensing element consists of three slab coupled optical-fiber sensors that are combined to allow directional electric field sensing. The packaged three-axis sensor has a small cross-sectional area of 0.5 cm×0.5 cm by using an x-cut crystal. A method is described that uses a sensitivity-matrix approach to map the measurements to field components. The calibration and testing are described, resulting in an average error of 1.5°.

Slab coupled optical fiber sensor calibration

This paper presents a method for calibrating slab coupled optical fiber sensors (SCOS). An automated system is presented for selecting the optimal laser wavelength for use in SCOS interrogation. The wavelength calibration technique uses a computer sound card for both the creation of the applied electric field and the signal detection. The method used to determine the ratio between the measured SCOS signal and the applied electric field is also described along with a demonstration of the calibrated SCOS involving measuring the dielectric breakdown of air.

Electro-optic polymer electric field sensor

Modern electronics are often shielded with metallic packaging to protect them from harmful electromagnetic radiation. In order to determine the effectiveness of the electronic shielding, there is a need to perform non-intrusive measurements of the electric field within the shielding. The requirement to be non-intrusive requires the sensor to be all dielectric and the sensing area needs to be very small. The non-intrusive sensor is attained by coupling a slab of non-linear optical material to the surface of a D shaped optical fiber and is called a slab coupled optical fiber sensor (SCOS). The sensitivity of the SCOS is increased by using an organic electro-optic (EO) polymer.

Advances in CPL, collimated plasma source, and full-field exposure for sub-100-nm lithography

In the world of micro- Lithography, several options exist for obtaining features below the 100nm level. Options include a variety of methods which range from additional process steps in etch, multilayer resist systems, or expensive throughput limited direct write E-beam systems. Each comes with a handful of trade offs in uniformity, repeatability and cost. Collimated (LASER) Plasma Lithography (CPL), on the other hand offers a full field exposure with minimal process intervention to obtain resolution below the 100nm barrier. CPL, uses a membrane 1x proximity mask and a collimated light source with energy peaking at 11 A°. By using a mask, an entire 22mm x 22mm field (30mm x 30mm with the next generation) can be exposed at once regardless of chip density, removing any throughput concerns as well as placement, stitching and typical E-beam machine flaw defects. Collimation, provides a predictable flux of energy to ensure minimal global divergence and energy level variation. Energy at 11 A°, allows for a high level of uniformity and penetration within the resist, without introducing resolution compromising scattering or standing wave effects. This Paper will demonstrate the capabilities of CPL as well as the advantages over traditional lithography in obtaining features below 100nm. We will also depict process techniques which take full advantage of improvements in CAR, and experiments which suggest reduction possibilities through variables in mask fabrication.

Compact super-wideband optical antenna

We present progress on advanced optical antennas, which are compact, small size-weight-power units capable to receive super wideband radiated RF signals from 30 MHz to over 3 GHz. Based on electro-optical modulation of fiber-coupled guided wave light, these dielectric E-field sensors exhibit dipole-like azimuthal omni directionality, and combine small size (<< λRF) with uniform field sensitivity over wide RF received signal bandwidth. The challenge of high sensitivity is addressed by combining high dynamic range photonic link techniques, multiple parallel sensor channels, and high EO sensing materials. The antenna system photonic link consists of a 1550 nm PM fiber-pigtailed laser, a specialized optical modulator antenna in channel waveguide format, a wideband photoreceiver, and optical phase stabilizing components. The optical modulator antenna design employs a dielectric (no electrode) Mach-Zehnder interferometer (MZI) arranged so that sensing RF bandwidth is not limited by optical transit time effects, and MZI phase drift is bias stabilized. For a prototype optical antenna system that is < 100 in3, < 10 W, < 5 lbs, we present test data on sensitivity (< 20 mV/m-Hz1/2), RF bandwidth, and antenna directionality, and show good agreement with theoretical predictions.

High-power laser-produced plasma source for nanolithography

JMAR develops Laser-Produced Plasma (LPP) sources for lithography applications, and has specifically developed Collimated laser-Plasma Lithography (CPL) as a 1 nm collimated point source and stepper system to address sub-100nm lithography needs. We describe the CPL source development, show demonstrated sub-100nm printing capability, and describe status of a beta lithography tool. The system will be power-scaled to address silicon device contacts and vias at 90nm and below. This development has much in common with LPP Extreme UltraViolet Lithography (EUVL) sources; an EUV source concept is presented to address the high power requirements of that Next Generation Lithography (NGL).

X-ray Spectral Measurements of the JMAR High-Power Laser-plasmaSource

X-ray spectra of Cu plasmas at the focus of a four-beam, solid-state diode-pumped laser have been recorded. This laser-plasma X-ray source is being developed for JMARs lithography systems aimed at high- performance semiconductor integrated circuits. The unique simultaneous overlay of the four sub-nanosecond laser beams at 300 Hertz produces a bright, point-plasma X-ray source. PIN diode measurements of the X-ray output indicate that the conversion efficiency (ratio of X-ray emission energy into 2π steradians to incident laser energy) was approximately 9 percent with average X-ray power yields of greater than 10 Watts. Spectra were recorded on calibrated Kodak DEF film in a curved-crystal spectrograph. A KAP crystal (2d = 26.6 Angstroms) was used to disperse the 900 eV to 3000 eV spectral energies onto the film. Preliminary examination of the films indicated the existence of Cu and Cu XX ionization states. Additional spectra as a function of laser input power were also recorded to investigate potential changes in X-ray yields. These films are currently being analyzed. The analysis of the spectra provide absolute line and continuum intensities, and total X-ray output in the measured spectral range.