To the best of our knowledge, it is the first butterflypackaged 1064 nm semiconductor laser that is stable enough to be locked to an external frequency reference. Apr 06, 2018 an external cavity laser, or ecl, is a laser with a reflector that creates the cavity outside of the gain chip and allows the cavity to be longer than if it was confined to the gain chip. The external cavity diode laser is designed to increase the modehop free frequency tuning range, and allow accurate frequency tuning and stabilisation. Both manufacturers and distributors can be registered. External cavity diode laser setup with two interference filters. A lowtemperature external cavity diode laser for broad. Aug 09, 2010 diodenlaser 405nm, sfaw210 mit externem resonator mit littrowaufbau. A semiconductor laser diode ld with a central wavelength of 698 nm is antireflection coated on its output facet and is combined with an external cavity, leading. The first external cavity diode lasers used intracavity etalons and simple tuning littrow gratings. We report a homebuilt external cavity diode laser ecdl, using a diode whose front facet is not anti reflection ar coated, that has a modehopfree mhf. An additional output coupling mirror in a vshape configuration of the resonator makes the system more efficient and convenient to operate. Optical locking to a filter cavity is an effective method to eliminate the limitations of an external cavity diode laser, such as broad spontaneous emission backgrounds and frequency jitters. An external cavity diode laser is a diode laser based on a laser diode chip which typically has one end antireflection coated, and the laser resonator is completed with, e. A total tuning range of typically 4 nm and an optical output power of up to 30 mw were observed after optimization of the external cavity.
Diodenlaser 405nm, sfaw210 mit externem resonator mit littrowaufbau. A tunable external cavity semiconductor laser is provided with a semiconductor laser diode, a diffraction grating and a movable mirror. We report a homebuilt external cavity diode laser ecdl, using a diode whose front facet is not antireflection ar coated, that has a modehop free mhf tuning range greater than 140 ghz. They are used in optical communication and fibre sensor technology.
Light emitted by a diode laser is not monodirectional and typically has a large bandwidth. The tafhg pro is a tunable, diodebased laser source in the deep uv spectral range. Modehopfree tuning over 140 ghz of external cavity diode. Schematic layout and photograph of discrete tunable external cavity laser. Abstract we report an external cavity diode laser ecdl, using a diode whose front facet is not antire. For detailed information regarding the laser design see 2.
A constant current source for an external cavity diode laser. While collimating the output of a diode laser is a relatively simple problem to solve with lenses, narrowing the bandwidth of the output requires construction of an external cavity. External cavity laser diodes ecls are lasers with a very small line width, very good wavelength stability, and very low noise. Beatnote measurements between this mfcecdl and a narrowlinewidth reference laser are performed and demonstrate that the linewidth of this mfc. Scholten1, 1arc centre of excellence for coherent xray science, school of physics, the university of melbourne, victoria 3010, australia 2school of physics, monash university, victoria 3800, australia corresponding author. Mode stability of external cavity diode lasers cdn. We based the design of our laser on plans outlined by r. External cavity diode lasers are tunable lasers which use mainly double heterostructures diodes of the al x ga 1x as type. We present a extendedcavity diode laser ecdl with kilohertz linewidth by optical feedback from a monolithic folded fabryperot cavity mfc. Another type of externalcavity laser uses a resonator based on an optical fiber rather than on freespace optics. External cavity diode laser with verylow frequency drift. Development of an interference filterstabilized externalcavity.
A laser diode, ld, injection laser diode ild, or diode laser is a semiconductor device similar to a lightemitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diodes junction 3 laser diodes can directly convert electrical energy into light. Design and development of an external cavity diode laser for laser. A diode laser is simply a light emitting diode led with a feedback cavity. Us5319668a tuning system for external cavity diode laser. Fang abstract in this report, a model of external cavity semiconductor laser is built, and then based on this model a program is coded for simulating the thermally induced wavelength shift and mode hopping. The performance achieved with multiple diode models addresses the scarcity of commercial red laser diodes below 633 nm, which is a wavelength range relevant to the spectroscopy of many molecules and ions. The laser system is based on a highpower gan diode laser in a littrow externalcavity. The quality of the ar coating and the interaction of the ld with the optical feedback critically in. Design and characterization of an external cavity diode laser for nvcenter photoluminescence excitation john raihala1,2 1institute of nuclear theory reu, university of washington, seattle, wa 98195 2department of physics, university of chicago, chicago, il 60637 the nitrogen vacancy nv center is a point defect in diamond which shows potential to be used. An externalcavity diode laser system with output power up to 3. We evaluated its performance from the viewpoint of precision experiments. The grating and piezo holder consists of three adjustable screws, two of the screws allow manual.
Main cavity constructed from a single aluminum block. An externalcavity diode laser is a diode laser based on a laser diode chip which typically has one end antireflection coated, and the laser resonator is completed with, e. A lownoise current source and a temperature controller for thermal stability were developed as part of the system since the output frequency changes with temperature and current. An external cavity diode laser sensor article pdf available in journal of lightwave technology 11. Pdf singlefrequency external cavity green diode laser. This book will appeal to undergraduate and graduate students, scientists and engineers alike. Realizing the pivot axis of the tuning grating and the cavity adjustement via flexmounts ensures the highest passive stability of our littrow laser system.
As noted above, the split cavity laser is relatively susceptible to external vibration. In our experiments, an mfc replaces the retroreflecting mirror in the traditional ecdl configuration. The laser will oscillate at a wavelength resonant with the external laser cavity between the diode rear facet and the grating. Tuning range and output power optimization of an external. Design and development of an external cavity diode laser. The laser system is based on a highpower gan diode laser in a littrow external cavity. Diode lasers unlike leds will not operate below a threshold current. When the frl is placed in an external cavity, the internal and external. Using an antireflectioncoated ingan device, a violet externalcavity. External cavity laser diodes fibrecoupled laser diodes. A littrow configuration external cavity diode laser. External cavity diode lasers ecdls have often been used for this purpose owing to their.
Pdf simple external cavity diode laser researchgate. Littman metcalf tunable external cavity diode laser, 630nm 2450nm, up to 100mw, patented technology, handsoff operation, large modehop free piezo tuning range, narrow linewidth, free space and fiber coupled versions. We present a stable design for an external cavity diode laser ecdl with an investigating the e ect of a rotating glass plate on the modehop free tunability. Due to the extreme sensitivity of laser frequency to cavity length 25mhznm for a 780nm diode, the grating mount, which is typically adjustable to allow for laser alignmentandtuning,shouldberigid. External cavity laser diodes fibercoupled laser diodes.
We describe the characteristics of the planarwaveguide external cavity diode laser pwecl. The practical and accessible information in this volume will enable the reader to study external cavity diode laser, to build up the systems of external cavity diode laser as well as to develop advanced systems for their particular applications. Osa external cavity diode laser with kilohertz linewidth by. The external cavity is realized with class d antireflection coated diode lasers and with a high efficiency diffraction grating. We achieved this using a short external cavity and by simultaneously tuning the internal and external modes of the laser. When transmitting data, the object is to get as much data from point a to point b as possible and do so at the lowest cost. Narrowbanded ecl lasers are characterized by a very small line width, low noise, and very good wavelength stability. A semiconductor diode laser having a modified littrow external resonator is described. Stable operation of the optical locking requires simultaneous control of the feedback phase and the diode laser frequency. Design of external cavity semiconductor lasers to suppress wavelength shift and mode hopping l. Compact tuneable external cavity diode laser ecdl with. Modehopfree fine tuning of an externalcavity diode. External cavity diode lasers ecdls realworld atomic sensors and other exacting applications require laser sources with specific size, environmental, and optical characteristics, placing unique constraints that most commercial laser systems do not meet. Modehopfree tuning over 5 ghz of external cavity diode.
Mode stability of external cavity diode lasers sebastian d. The external cavity diode laser including mechanical components and control electronics of the system is developed from basic components. It has been well established that the continuous modehopfree. Pdf antireflectioncoated blue gan laser diodes in an. Weiman a 2001 nobel laureate demonstrating that the linewidth of a diode laser. Design and characterization of an external cavity diode laser. We achieved this by using a short external cavity and by simultaneously tuning the. Osa external cavity diode laser with kilohertz linewidth. Both laser diode and dmd are located in the focal plane of the lenses, making the angular tolerances of the optical components quite forgiving for the entire cavity. Thus, by using optical feedback from a diffraction grating, we are able to narrow the total bandwith. The system consists of an external cavity diode laser, a high power semiconductor amplifier ta, and two cascaded. External cavity diode laser spectrum in modehopfree.
To get high speed transmission, we use light but not just any light we use lasers. Both a holographic diffraction grating and a ruled diffraction grating are used as feedback elements in the. The internal cavity modes of the laser diode are typically spaced by around 100 ghz and the internal mode that experiences maximum gain determines the emission wavelength of the frl. Where to buy externalcavity diode lasers, ecdl, narrow. A planar nematic liquid crystal nlc cell is incorporated into a littmantype external cavity as the wavelengthtuning device for a semiconductor laser diode. A narrow linewidth externalcavity diode laser system was achieved around 405 nm in 2007, with an.
Construction and characterization of external cavity diode. Characteristics of the singlelongitudinalmode planar. Pdf design and development of an external cavity diode. Pdf improving an external cavity diode laser design semantic. We report on the design and characterization of a lowtemperature external cavity diode laser ecdl system for broad wavelength tuning. Painter california institute of technology abstract anenhancedtunablelittrowcon. Check our arcoated diode stock list for availability.
Due to their wide tunability and narrow linewidth, dye laser and tisaphire lasers were the only primary laser sources in amo physics back in 1980s. The linewidth was measured with a beterodyne technique, and 0. Tunable external cavity diode laser littrow configuration. We report a homebuilt external cavity diode laser ecdl, using a diode whose front facet is not antireflection ar coated, that has a modehopfree mhf tuning range greater than 140 ghz. External cavity diode laser setup with two interference. The free running laser frl has a broad gain profile typical width 10 nm. Stable operation of the optical locking requires simultaneous control of the feedback phase and the diodelaser frequency. A tuneable external cavity diode laser ecdl comprises a diode laser chip an optical gain medium with antireflection coating on one or both facets and optics for coupling the output of the gain medium to the free space of the external cavity. Design and characterization of an external cavity diode.
Manual tunable littmanmetcalf diode laser system sacher laser. Pdf mode stability of external cavity diode lasers researchgate. Both laser diode and dmd are located in the focal plane of the lenses, making the angular tolerances of. We have seen in a previous article that external cavity diode lasers ecdl have a narrowlinewidth laser spectrum. Modulationfree optical locking of an externalcavity diode. Modehopfree tuning over 140 ghz of external cavity diode lasers. Optical locking to a filter cavity is an effective method to eliminate the limitations of an externalcavity diode laser, such as broad spontaneous emission backgrounds and frequency jitters. Antireflectioncoated blue gan laser diodes in an external. Commercially available ganbased laser diodes were antireflection coated in our laboratory and operated in an external cavity in a littrow configuration. In this project we have created an external cavity diode laser ecdl, which selects a single wavelength from the entire output spectrum of the diode laser and drives the laser at this wavelength.
Miniature selfaligned external cavity tunable single. Tuning this cavity length across a wavelength allows the laser to be tuned across a free spectral range c2 l around the grating gain peak where c, is the speed of light and l, is the cavity length, typically 1. In both designs laser diodes with and without antireflection ar coating were employed. Characteristics of the singlelongitudinalmode planarwaveguide external cavity diode laser at 1064 nm kenji numata,1,2, mazin alalusi,3 lew stolpner,3 georgios margaritis,3 jordan camp,2 and michael krainak2 1department of astronomy, university of maryland, college park, maryland 20742, usa 2nasa goddard space flight center, greenbelt, maryland 20771, usa. The laser is based on an external cavity diode laser ecdl system using a commercially available ganbase d highpower blue laser diode emitting at 448 nm. Compact tuneable external cavity diode laser ecdl with diffraction limited 500 mw, and their application in bec and crds sandra stry, richard knispel, lars hildebrandt and joachim sacher sacher lasertechnikgroup, hannah arendt str. Modulationfree optical locking of an externalcavity. Consequently, only when the threshold current is reached will the diode commence lasing. External cavity diode lasers offer more stable output frequency and narrow. However, since a series pioneer work on external cavity diode laser ecdl in 1990s, particular those by c.
The output power is coupled out via the rear facet of the laser chip for avoiding any beam walk. Tuning range and output power optimization of an externalcavity. Robust external cavity diode laser ecdl and their application in. Pdf a semiconductor diode laser having a modified littrow external resonator is described. External cavity diode laser for ultracold atom experiments. Design and development of an external cavity diode laser for. This results in the best performance for an external cavity diode laser system in littrow configuration. Ideally, the laser is also single mode, meaning we are outputting laser light in a very narrow range of frequencies and only those frequencies. By varying the driving voltage of the nlc cell and laser diode bias current simultaneously, we demonstrate singlemode oscillation and modehopfree tuning over 19. Driven by voltage, the doped pntransition allows for recombination of an electron with a hole.
Mode stability is an important performance characteristic of external cavity diode lasers ecdls. The diode laser is positioned to illuminate a diffraction grating and a movable mirror is positioned to reflect a selected wavelength back into the cavity. They are used in optical communication and fiber sensor technology. The external cavity diode laser is designed to increase the modehopfree frequency tuning range, and allow accurate frequency tuning and stabilisation. As a result, we achieve a robust and highly stable external cavity diode laser system with excellent values for the long.