Newport Spectra-Physics Newsletter - #31 - November 2009 - (Page 6)

Page 6 November 2009 w w w. n e w p o r t . c o m Do You Need to Modulate Your Beam? A typical setup for observing phase modulation: a HeNe laser beam is sent through a New Focus Model 4001 resonant phase modulator operating at 29 MHz, and the beam is focused into an optical spectrum analyzer. The laser’s phase-modulated spectrum, with its characteristic frequency sidebands, is observed on an oscilloscope. M O D U L A T O R S Modulators can be used in a variety of applications. In measurement systems, amplitude modulators can be used as actuators to hold the intensity in a laser beam constant, or as optical choppers to produce a pulse stream from a CW laser beam. Phase modulators are used to stabilize the frequency of a laser beam, or to mode-lock a laser. New Focus™ offers an extensive, high performance E-O modulator line, including both phase and amplitude modulators, between 500– 1600 nm, with RF drivers and accessories. input with a broad wavelength range, which makes it a good general lab tool for modulating signal up to relatively low 200 MHz frequency. To learn more about fundamentals of electro-optic modulators, please read our Application Note #2. WEB High-Voltage Amp. Download the Application Note #2. Please click here. What is an electro-optic modulator? Electro-optic amplitude and phase modulators allow you to control the amplitude, phase, and polarization state of an optical beam electrically. Unlike direct modulation of the laser itself, external modulators do not cause any degrading effects on laser linewidth and stability. New Focus manufactures electro-optic amplitude and phase modulators using lithium niobate, LiNbO3, and lithium tantalate, LiTaO3 — two crystals with high electro-optic coefficients and good optical and electrical properties. PZT Mixer Photodetector Oscillator Fabry-Perot Resonator Source Laser Resonant modulator vs broadband modulator? A resonant modulator operates at a specified frequency while a broadband modulator can operate over a wide frequency range. In a resonant modulator, the crystal is placed in a resonant circuit or cavity tuned to a particular frequency. Because the crystal voltage can be more than ten times the input drive voltage when operating near that particular frequency, resonant devices require significantly lower input voltage, and are easier to operate than broadband modulators. Keep in mind that the resonant frequency of the Model 4001 and 4003 modulators isn't tunable. Typically the resonance has a bandwidth of 2–4% of the resonant frequency, allowing the device to be operated over this narrow frequency range. In contrast, the high-frequency resonant cavity modulators (Models 442X, 443X and 485X) are equipped with a tuning screw that allows the resonant frequency to be adjusted over a 100 MHz range. The broadband modulators accept optical Phase Modulator Model 400X or 406X Beamsplitter Diagram for a Pound-Drever-Hall laser-frequency-stabilization system. Model 410X Amplitude Modulator Optically Chopped Signal Laser Photoreceiver Models 1801, or 1811 V = ±15 V Glan-Thompson Polarizer Sample Function Generator 1 MHz Lock-in Amplifier Signal Out Using an amplitude modulator as a high-frequency optical chopper. Family of Brands — Corion® • New Focus™ • Oriel® Instruments • Richardson Gratings™ • Spectra-Physics®

Table of Contents for the Digital Edition of Newport Spectra-Physics Newsletter - #31 - November 2009

Cover and Contents
- Newport Corporation Starts Direct Selling of New Focus Products in Europe
- Mai Tai® SP Short Pulse One Box Amplifier Seeder
- Spitfire® Pro XP 7 W Ultrafast Ti:Sapphire Amplifier
- TLB-7000 StableWave™ Tunable Lasers
- TA-7600 Series Tapered Amplifiers
- SCG-800-CARS Supercontinuum Generation Fiber Device
- Newport 3700 High-Power Temperature Controller
- Newport High-Power Laser Diode Control Kits
- Do You Need to Modulate Your Beam?
- High-Damage-Threshold Phase Modulators (KTP)
- New Focus Amplitude Modulators
- New Focus 981x Stability™ Top and Center Mounts
- New Focus Flipper™ 1” and 2” Optical Mounts
- Open Cage System
- Newport Broadband Metallic Mirrors
- Ultra-Broadband Dielectric Mirrors
- Ultrafast Laser Super-Broadband Turning Mirrors
- New Focus UV Excimer Mirrors
- New Focus Nd:YAG Mirrors
- S-2000-TC Stabilizer™ Isolators
- LABasix™ SA2 Series Aluminum Breadboards
- Picomotor™ Actuators
- iPico™ New Focus Intelligent Picomotor Modules
- New Focus Kinematic Stages
- Motorized Kinematic Stages
- New Focus GuideStar™ Beam Stabilization
- UMR-TRA XY Compact Motorized XY Stage
- URB100CC High-Speed Precision Rotation Stage
- HXP100-MECA Newport Hexapod
- Motion Control Capability Brochure
- 818P-500-55 500 W Fan-Cooled Thermopile Detector
- 818P-3KW-060 Water-Cooled Thermopile Detector
- 818P-001-12NIR Thermopile Sensor, 1 μW–1 Watt
- LBP-HR High Resolution CCD Laser Beam Profiler
- 80 MHz Balanced Photoreceivers
- Nirvana™ 125 kHz Auto-Balanced Photoreceivers
- LED Scribing The Illumination Revolution
- Oriel® IQE-200™ Quantum Efficiency Measurement System
- PVIV-TC-VAC Temperature Controlled Vacuum Chuck KitMémentos - LMD
- Workstation for Laser Direct-Write Processing
- Photoresponse Mapping of Photovoltaic Cells
- Raman Microspectrometer
Literature Request

Newport Spectra-Physics Newsletter - #31 - November 2009