Acoustooptic effect and its use in signal processing. In our experiment, the acousto optic interaction length of the aom designed primarily for operation in such a mode was 2 mm. Acousto optic material selection a variety of acousto optical materials are used for acousto optic modulators depending on the laser parameters such as wavelength, polarization, and power density. Each aom model has an rf driver made specifically for it. Acoustooptic modulators selection guide engineering360. Acoustooptic modulator driven by surface acoustic waves. Highlights excellent performance is achieved through the use of highfrequency, bulk wave transducers and specialized fabrication techniques. Sep 05, 20 a fun experiment transmitting sound waves via modulated laser light. In an aom a laser beam is caused to interact with a high frequency ultrasonic sound wave inside an optically. An acousto optic modulator aom is an optical element that modulates the frequency of light by an applied signal, usually in the rf range. We offer fiber coupled acousto optical modulators aom. This website is made to help user to understand basic principles of acousto optic theory, on which acousto optic devices are based on. Acousto optic modulation using a new chlorotellurite glass.
For materials with a fixed acoustic velocity, the acoustic wavelength is a function of the frequency of the drive signal. Rovisco pais 1, 1049001 lisboa, portugal abstract acoustooptic components use a range of different materials in a variety of configuretions. Pdf this paper presents a new type of acoustooptic modulator based on the conjunction of a piezoelectric contour mode resonator cmr. The dualbeam infrared acousto optic modulator from isomet springfield, virginia, usa is a new acousto optic beam steering technique that allows. Rf driver power supply for the rf driver function generator or other variable voltage source for controlling the rf driver function generator square wave at modulation frequency dc power 24 v, 0. The rf driver features all the necessary components to drive the modulator with analog or. Bulkwave acoustooptic bragg diffraction, in guidedwave acoustooptic interactions, devices and applications,ed.
Shaper board for eom driving, combining a laser diode driver, a multiple. A is a world leader in the manufacturing of quality acoustooptic and radio frequency devices. The 9031m is exceptionally compact, having a 36 x 61 x 25 mm envelope yet still provides all six degrees of motion in a single device. Acoustooptic modulators by virtue of having no moving parts our acousto optic devices are able to amplitude modulate a laser beam at very high speed. The driver accepts an analog modulating signal at baseband video frequency and provides a doublesideband amplitudemodulated rf output to the acousto optic modulator at a particular center frequency. We combine extensive ao device design experience with strict manufacturing. Acoustic wave surface acoustic wave diffraction efficiency optical beam optical wave. An acoustooptic modulator aom is a device which can be used for controlling the power of a laser beam with an electrical drive signal. Modulation transfer spectroscopy based on acousto optic modulator with zero frequency shift to cite this article. Bulkwave acoustooptic bragg diffraction, in guidedwave acoustooptic interactions, devices and applications, ed. Basic acousto optic modulator and driver rf 1st order output 0th order input laser beam intensity modulation sep bragg modulator driver ao modulator key parameters. Acousto optic effect, also known in the scientific literature as acousto optic interaction or diffraction of light by acoustic waves, was first predicted by brillouin in 1921 and experimentally revealed by lucas, biquard and debye, sears in 1932. The products available from ams technologies feature very high switching speed and excellent diffractive efficiency and thus maintain laser performance.
Dynamic optical tweezers using acoustooptic modulators. Acoustooptic modulation for sound transmission youtube. A is a world leader in the manufacturing of quality acousto optic and radio frequency devices. Rise time, modulation rate, beam diameter, and power handling needs of the application need to be understood in order to identify the best acousto optic modulator and rf driver solution. Acousto optics is a branch of physics that studies the interactions between sound waves and light waves, especially the diffraction of laser light by ultrasound or sound in general through an ultrasonic grating. Acoustooptic modulators aom allow the intensity of light to be controlled and modulated at rates that far exceed mechanical shutters, even up to 70 mhz. Then a detailed discussion on three basic types of acoustooptic devices is presented.
When coupled with a companion driver module from the cti model series, they provide an easyto. Applying a voltage across the electrodes of an electro optic. Background acoustooptic devices are based on the periodic modulation of the optical index of refraction caused by an acoustic wave propagating in a transparent material. Doublepass acoustooptic modulator system aa opto electronic. Such multiple closely spaced laser lines are important. When coupled with a companion driver module from the cti model series, they provide an easytouse combination for a wide variety of applications. We present to the reader the mathematical formalism used to describe this phenomena as well as the common. Bhave oxidemems lab, cornell university, ithaca, new york, usa abstract frequency modulation of a continuous wave laser source enables generation of photons at multiple frequencies from a single pump laser. Crystal technologys cti acousticoptic modulators of the model 3000 series provide a reliable, economical means for amplitude modulation of laser light. Our proprietary optical and electrical designs minimize crosstalk, allowing concurrent operation of up to 48 channels for modulation, and up to 8 channels for. An optional integrated frequencydoubling module that provides conversion efficiencies up to 40% further extends the capabilities of the pulse switch. The ability of the acousto optic modulator to shift the frequency of a laser light beam by a precise and stable amount is crucial to production of a beat note from two light beams in this experiment.
Depending on the selected bragg angle, these devices will either upshift or downshift the laser light by the frequency of the applied rf signal. They are used in lasers for qswitching, telecommunications for signal modulation, and in spectroscopy for frequency control. Table 2 is a summary of the properties and figure of merit for most common materials used for the neos technologies acousto optical modulators. Acoustooptical effects principles and applications.
Introduction to acousto optic modulators by olen rambow september 20 omycroft. So, now if we combine these into this expression of delta n, which is given by this we have seen earlier that the peak change in the refractive index. Pdf acoustooptic modulation using a new chlorotellurite. The rf driver features all the necessary components to drive. Qswitches fiber pigatailed versions are also available. A tutorial introduction to optical modulation techniques. When the strain is generated by an acoustic compression or rarefaction, an aom is formed. A guide to acoustooptic modulators nickerson devices. Optical setups require extreme precision, and researchers must often implement modulators to adjust the frequency, amplitude, wavelength, and direction of their laser beam. By applying a digital ttl signal to the modulator s driver digital modulation input, the rf energy applied to the modulator is modulated on and off. Pdf acoustooptic infiber modulator using acoustic focusing.
Our acousto optic modulators are optimized for low scatter and high laser damage threshold. Acoustooptic modulators by virtue of having no moving parts our acoustooptic modulators aoms are able to amplitude modulate a laser beam at very high speed. This grating structure causes diffraction of the guided optical waves, resulting in modulation or switching. This paper presents an overview of the characteristics of several types of multibeam modulators based on optical diffraction including multifrequency ao, multiport ao, and e0 modulator arrays. An introduction to acoustooptics scott e pollack physics 7810 fundamentals of optics and lasers university of colorado, boulder december, 2002 abstract this paper is a brief introduction to acousto optic phenomena.
Mar 03, 2012 advantages of ea modulators zero biasing voltage low driving voltage lownegative chirp high bandwidth 14. Such compact devices can be used as phase modulators in a wide range of applications in laser spectroscopy, where the frequency noise reduction of a variety of the lasers is essential. An acousto optic modulator aom uses the acousto optic effect to diffract and shift the frequency of light using sound waves usually at radiofrequency. Acousto optics modulators fibre coupled acousto optics.
Dynamic optical tweezers using acoustooptic modulators juliaferrerortas fig. A key element in any such device is the transducer which converts the electrical drive signal to the acoustic wave. Multichannel acoustooptic modulators are used to independently modulate an array of light beams for photolithographic printing, optical computing, and signal processing applications. Acousto optic modulators by virtue of having no moving parts our acousto optic devices are able to amplitude modulate a laser beam at very high speed.
All our optical modulators are based on the electro optic or pockels effectthe linear dependence of the index of refraction on an applied electric. Allfiber and fiber compatible acousto optic modulators with potential biomedical applications. The modulation is a result of bragg di raction caused by the light wave interacting with a sound wave created by the transducer. Because the acoustic signal is sinusoidal, a moving. We also offer liquid crystal eo modulators for speeds up to 2. Paper modulation transfer spectroscopy based on acousto. Charts showing the characteristics of acousto optic scanning devices, acousto optic figures of merit, and solutions for common problems with acousto optic processor devices. Mccarron december 7, 2007 1 introduction acousto optic modulators aoms are useful devices which allow the frequency, intensity and direction of a laser beam to be modulated. The principle behind the operation of acoustooptic tunable filters is based on the wavelength of the diffracted light being dependent on the acoustic frequency. The devices listed are aimed at fibre optic telecommunications applications but we can also offer fibrecoupled versions of our standard aoms, if required.
This phenomenon, known as the acoustooptic ao dif fraction, has led to a. Pdf the combination of ultrasound and optics, together with statistics, now permits light. New focus offers a broad line of optical modulators and drivers that are versatile, reliable and easy to use. This includes modulators, deflectors, tuneable filters, frequency shifters and qswitches. The effect of input phase modulation to a phasesensitive optical. Off modulation for fast switching or variable level modulation to provide proportional intensity control. Acousto optic devices are finding increasing application as deflectors, modulators, qswitches and mode lockers in laser systems. Acousto optic modulators acousto optic modulators aom allow the intensity of light to be controlled and modulated at rates that far exceed mechanical shutters, even up to 70 mhz. A different approach to modulator technology uses the interaction between light and sound waves to produce changes in optical intensity, phase, frequency, and direction of propagation. Acoustooptic tunable filters aotfs florida state university. The substrate is held down on the stage by vacuum and moves in the xy plane. The basic operating principles apply to all ao types. The proposed aom is based on the short length of the claddingetched fiber, the ends of which are fixed on a slide glass.
The performance requirements are optimised by selecting the crystal material and. Acoustooptic application note modulator model 3000 series this data sheet is issued to provide outline information only and crystal technology, inc. We offer a broad range of acousto optic modules that can be used as. In the preceding chapter, we have shown that modulators and switches can be made by using the electro optic effect to produce a gratingshaped variation of the index of refraction within the waveguide.
Micropg 101 pattern generator standard operating procedure. An acousto optic modulator aom is a device which can be used for controlling the power of a laser beam with an electrical drive signal. Acoustooptic material selection a variety of different acousto optic materials are used depending on the laser parameters such as l aser wavelength optical transmission range, polarization, and power density. Those light waves may be sent through a transparent medium as a laser beam, or contained within a fiber optic cable. Acousto optic modulators are based on the diffraction of light by a column of sound in a suitable interaction medium. The authors describe acoustooptic modulators for optical fibers, fabricated by the deposition of thin zinc. The basic idea behind electrooptic devices is to alter the optical properties of a material with an applied voltage in a controlled way. Acoustooptic tunable filters aotfs the integration of optoelectronic technology into confocal microscopy has provided a significant enhancement in the versatility of spectral control for a wide variety of fluorescence investigations. Thorlabs selection of electro optic eo modulators includes freespace and fibercoupled linbo 3 modulators. The 9031m is a sixaxis aligner that allows intuitive adjustment of optical axes that comprise an input and an output e. Freespace amplitude, phase, or resonant modulators can operate at speeds up to 100 mhz. Acousto optic frequency shifters aofs are compact devices designed specifically for this task.
For example modulation bandwidths in excess of 50mhz are readily achievable. The important subject of acoustooptic materials is discussed in the section following. Acoustooptic infiber modulator using acoustic focusing. Acousto optic devices create an optical grating in a crystal by means of acoustic waves and can thus be used to change direction, frequency and intensity of a laser beam. Acoustooptic modulation of photonic bound state in the. Chapter 12 handbook of optics photonics research group. Piezoelectric transducers for acoustooptic applications. Within these devices incoming light bragg di racts o acoustic wavefronts which propagate through a crystal. This angle is in the plane of deflection and relative to a normal from the input optical surface. Rp photonics encyclopedia acoustooptic modulators, aom. Aa optoelectronic offers its customers solutions from prototype design to large volume manufacturing thanks to its internal resources.
Multibeam acoustooptic and electrooptic modulators enable ideband laser recording and optical data processing with reduced speed mechanical scanning. This acts like a phase grating, traveling through the crystal at the acoustic velocity of the material and with an acoustic wavelength dependent on the frequency of the rf. We also offer fibercoupled acousto optic modulators. The optical setup utilizes a singlemode diode laser 375 nm as its light source. Acousto optics and applications acoustooptic modulator driven by surface acoustic waves s. Acousto optic modulators by virtue of having no moving parts our acousto optic modulators aoms are able to amplitude modulate a laser beam at very high speed. This is one of the most useful properties of the acoustooptic modulator.
Our modulators are optimized for low scatter and high laser damage threshold. Free space acousto optic modulators the brimrose free space acousto optic modulator aom with rf driver is used to vary and control laser beam intensity. All ao devices apply a frequency shift to the diffracted output beams. Alultibeam acoustooptic and electrooptic modulators. Electro optic modulator an electrooptic modulator is a device which can be used for controlling the power, phase or polarization of a laser beam with an electrical control signal. A practical problem that arises when using acoustooptic modulators aoms to scan the laser. Acousto optic multichannel modulators aomc allow multiple beams to be modulated or deflected independently by integrating an array of transducers with a single acousto optic crystal. These acousto optical devices have different applications like beam deflection, frequency shifting of the input beam. Kakio interdisciplinary graduate school of medicine and engineering, university of amanashi,y kofu 4008511, japan in this paper, an introduction to the design, fabrication, evaluation, and application of acousto optic. Acousto optic modulator aom uses a sound wave to modulate an incoming beam of light to optimize optical systems and devices. By tuning the frequency of the acoustic wave, the desired wavelength of the optical wave can be diffracted acousto. Alignment problems with aommodulated laser beams can be effectively eliminated by using the aom in the doublepass con.
Acousto optic modulation acousto optic devices are primarily used for controlling laser beams. B 27 114203 view the article online for updates and enhancements. In an acoustooptic modulator aom a laser beam is caused to interact with a. Included in the discussion are the topics of deflectors, modulators, and. This is due to the increasing availability and performance of lasers, which have made the acousto optic effect easier to. An acoustooptic modulator can be used to shutter a laser beam on and off. An acousto optic modulator aom, also called a bragg cell, uses the acousto optic effect to diffract and shift the frequency of light using sound waves usually at radiofrequency.
It uses acousto optic modulators to adjust the laser intensity, and acousto optic deflectors to scan the beam. In conclusion, acousto optic modulation of cavityenhanced photonic bound states in the continuum in both the unresolved and resolvedsideband regimes has been demonstrated for. An allfiber acousto optic modulator aom, which features a compact structure and a lowdriving voltage, is experimentally demonstrated for the active modelocking of a fiber laser. Table 1 is a summary of the most common materials used for brimroses acousto optic modulators. Acousto optic modulators are devices that use sound waves to modify the amplitude, frequency, or phase of light passing through an acousto optic material. Bragg scattering for most practical applications of acousto optic modulators, the bragg description of the modulation process is a good approximation to the behavior of the system. Acousto optics is a phenomenon which deals with the interaction of light optics and sound acoustics. An interesting design is to combine the preceding techniques of tangential phase. Optical modulation a tutorial introduction to optical modulation techniques by gary breed editorial director t his article introduces the subject of optical modulation, the process of applying information to a light wave. Depending on the optical property of the material changed for light modulation, primary modulators can be categorized as absorptive modulators or refractive. Optical modulators with twodimensional layered materials. For proper modulator operation, the optical beam and sound. Acoustooptic modulators aoms are useful devices which allow the fre quency, intensity and direction of a laser beam to be modulated. It is electronically programmable using a microprocessor connected to the brimrose rf driver unit.
Pdf integrated piezoelectrically driven acoustooptic modulator. The acousto optic modulator the acousto optic modulator is based on the elasto optic effect, in which a material strain causes a change in the refraction index of the material. Free space acoustooptic modulators mhz electronics. Aom acoustooptic modulators, eom electrooptic modulators, soa. A practical problem that arises when using acoustooptic modulators saomsd to scan the laser frequency is the dependence of the beam diffraction angle on the modulation frequency. They are used in lasers for qswitching, telecommunications for signal modulation, and in. Acousto optic modulator 41145 an acousto optic modulator aom, also called a bragg cell, uses the acousto optic effect to diffract and shift the frequency of light using sound waves usually at radiofrequency. Where to buy acoustooptic modulators, aom, rf driver. The basic idea behind electro optic devices is to alter the optical properties of a. An rf signal applied to a piezoelectric transducer, bonded to a suitable crystal, will generate an acoustic wave. It is known that the output radiation has a pure fm spectrum. Acousto optic modulators aom are used to control laser beam intensity. In the preceding chapter, we have shown that modulators and switches can be made by using the electro optic effect to produce a gratingshaped variation of the index of refraction within the.
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