ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Types of Laser Diodes and their uses

Updated on January 12, 2012

5.6mm Laser Diode

5.6mm visible laser diode
5.6mm visible laser diode

Visible Diode Lasers

There are many different types of laser diodes. They vary in their structure, emission color or frequency and output power. The laser diode itself was first produced in 1962. Laser diodes, in contrast to Light Emitting Diodes (LED’s) are coherent light sources, that is, they emit light in one direction only. LED’s are like any other sort of light; incandescent bulbs, halogen or fluorescent, which emit their light in all directions.


To understand better how laser diodes are made, I have found many articles, this being one of them: http://www.madehow.com/Volume-6/Semiconductor-Laser.html by — Laurel M. Sheppard


There are many difference types of laser diode, each with a different arrangement of semiconductor layers. The basic type which uses two semiconductor layers is very inefficient. Better designs have multiple layers which increase the laser power by combining more charge carriers and trapping more light inside the waveguide. The most common types of laser diode are the heterostructure, quantum well, and distributed feedback.


While laser diodes are sometimes called semiconductor lasers, they are not usually called solid-state lasers. In electronics, solid-state and semiconductor generally mean the same thing. However, lasers are defined by the type of material used to produce their light and solid-state lasers use materials like ruby. While the power of a single laser diode is low, many can be grouped together to form a single high-power laser.


Laser diodes are most commonly used in optical media players to read data from CDs, DVDs, HD-DVDs, and Blu-ray discs. They are used to produce the light pulse that travels through optical fibers to link computer networks together. Laser printers use laser diodes to create the static charges that attract toner particles to their print drums. Handheld laser pointers used for presentations use laser diodes, and they are used in devices that measure distances and check levels. More powerful laser diodes are used in surgery to precisely burn tissue, and in manufacturing to cut and etch materials.


The laser diodes we use in our systems are all “visible” wavelength (color) lasers. The first CD-ROMs used a 780nm (near infrared) laser diode to read/write to the optical surface of the disk. The 780nm laser diodes were also commercially used in most laser printers to charge the drum by scanning the beam on/off across the drum thereby charging it to accept or not accept toner to create the document.


The first mass use of Visible diode lasers were for low powered 670nm (dark red) low output power (1-5mW) laser pointers and newer CDROM’s. As the wavelength gets shorter (i.e. 780nm is a longer wavelength than 670nm, the beams focus ability gets smaller allowing for a smaller spot size and more data to be read and written to disks. From this point, companies began to research shorter wavelength laser diodes in 650nm, 640nm and then 635nm. As previously stated, as the spot size decreases, the data that can be written on a disk is increased. The 635nm (red/orange) was particularly useful as it became a suitable replacement for older helium-neon gas lasers which emitted their laser light at 632.8nm (red/orange). These eventually made it into the laser pointer market as well. The closer the actual color or wavelength of a laser approaches 550nm (green), the more perceptible to the human eye’s curve.


For example, when you driving in day or nighttime, which light do you see on the traffic light easiest? It should be green, yellow then red. This is how the rods and cones in our retina work.


In the mid-2000s, many companies such as Nichia, Sanyo and others worked tirelessly to produce lasers which omit laser light in the blue violet range. This was a quantum leap in technology and a big physics hurdle. Laser diodes with wavelengths from 400-460nm are now available with moderate to high output powers. These became mass produced for use in new Blue ray disks and laser projectors.


Looking at green for a second, it has only been since 2009 since research has led to a direct green laser at 531nm. It is still in prototype and research, but will eventually get into mainstream products. This gap in green lasers was solved by using a technique known as Diode Pumped Solid State Lasers or DPSS. In this case, an 808nm laser is used to Pump a Vanadate or similar crystal, then a KTP crystal. Within this small cavity, the 808nm light is turned into 1064nm (high infrared), then passed through the KTP non-linear crystal and frequency doubled to 532nm green. These lasers are the basis for 99% of all 532nm lasers now in market, as well as the cheap green laser pointers. Remember these green lasers appear very bright. If you look at a green dpss laser side by side the same output power blue or red laser, the green appears much brighter. Once again, this is due to how our eyes see color.


The lasers we sell all use visible diode lasers (except for the DPSS green), our wavelengths include.


405 nm – Blue-violet laser, in Blu-ray Disc and HD DVD drives


445 nm – Deep blue laser multimode diode recently introduced (2010) for use in mercury free high brightness data projectors


532nm Green DPSS lasers


635 nm – Red/orange AlGaInP


640 nm – High brightness red


650nm – Red


Our lasers are all fitted into precision mounted heatsinks and potted with thermally conductive epoxy, air cooled and thermoelectrically cooled to provide long term use by the best heat dissipation methods.


Each laser has an adjustable collimation lens in front of the laser assembly. A collimator is a device that narrows a beam of particles or waves. To "narrow" can mean either to cause the directions of motion to become more aligned in a specific direction (i.e., collimated or parallel) or to cause the spatial cross section of the beam to become smaller.


In addition, since all visible diode lasers emit their coherent light in a stripe, the resulting beam looks like an ellipse or rectangle. We offer beam shaping optics to remove this aberration for a “roundish” shape.


I hope I have given some useful information on laser diodes. Our laser diode products can be found on our website







Comments

    0 of 8192 characters used
    Post Comment

    No comments yet.

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://maven.io/company/pages/privacy

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
    ClickscoThis is a data management platform studying reader behavior (Privacy Policy)