INFRARED 700nm - 4.9m

NOTE: If you're looking for the Roithner Lasertechnik IR LEDs with strange wavelengths, they can be found near the bottom of this page as well as on this one.

Radio Shack # 276-143, retail $1.99
Purchased 03-21-09, tested 03-24-09
I purchased this LED solely to perform spectroscopy of it.

Wavelength is too long for me to measure the power output with the instruments at my disposal, but the packaging materials state it as 16mW minimum with the LED's If (forward current) at 100mA.


I attempted to take a beam photograph with the digital imager (camera) from my ProMetric beam cross-sectional analyser, but as you can see, I met with rather limited success.
Beam angle is advertised at 45.


Spectrographic plot
Spectrographic analysis of this LED.
Advertised peak wavelength is 940nm, however this chart shows it to be closer to 925nm.



Hewlett-Packard, model # QSDL-E103
Received & tested 01-20-07
A fan of this website sent me ten of these LEDs for spectrography.
Neither of my digital cameras will give a beam photograph - not even a crappy one. So that's why there is no beam photograph here.
When driven with an If of ~70mA, a dull, dim, deep cherry red glow was visible.

According to the supplied data, these LEDs were manufactured in December 1995.

Spectrographic plot
Spectrographic analysis of this LED.
This is an ~860nm LED, so there's little "tail" on this chart.
Ocean Optics USB2000 Spectrometer on loan from WWW.TWO-CUBED.COM.



www.irdevelopment.com, model (model # not shown on website), price $0.79
Received 02-02-04, tested 02-04-04
I received 10 of these LEDs a couple of days ago from David K. in Oregon, so here ya go...
This LED comes in a standard looking 5mm (T1 3/4) clear epoxy case. The advertised peak wavelength is 920nm, in the near-infrared portion of the spectrum. I tried to get a beam picture for this website, but was not able to. So here's a picture of the LED itself.


Looks rather ordinary, doesn't it? ;-)

These LEDs are said to output 27mW/steradian. I am not equipped to measure LED power at wavelengths like this, so I cannot confirm this reading.
Here's the link to this LED on their webstore.

The specs for this LED, as printed on the ESD bag they came in, are as follows:

Hi Power Nightvision Infrared LEDs
920 Nanometer
1.5 Volts Nominal
30 Milliamps Nominal 50 Milliamps MAX
NOT VISIBLE WITHOUT NV DEVICE



Spectrographic plot
Spectrographic analysis of this LED.



Roithner Lasertechnik, model ELD-920-515-1, price TBA
Here is another near-IR LED with a really unusual wavelength: 920 nanometers!
Roithner Lasertechnik specialises in LEDs with all kinds of funny wavelengths you can't find anyplace else, and this LED is one of them.

closeup of 920nm LED die
This is a photomicrograph I took of the LED's die while it was turned on. This is right at the outer edge of my new Nikon camera's radiation sensitivity, and the camera renders the IR radiation at this wavelength as a nasty shade of pukey sage green. You would *not* see anything with the eye, other than a very dull, deep cherry red glow if you're one of those who can just barely see into the near-IR. (You can tell if you're "one" if you can see a dull cherry red glow from a Radio Shack "high output" IR LED at 880nm).

The general specs of this LED go as follows:
    MAXIMUM RATINGS:
      Forward current: 100mA
      Peak forward current: 200mA
      Surge forward current (<10uS): 2 amps
      Reverse voltage: 5 volts
      Operating temp: -55C to +100C

    OPTICAL & ELECTRICAL (at 100mA):
      Forward voltage: 1.5 volts typical
      Radiant power: 32 milliwatts
      Peak wavelength: 920nm
      Spectral line halfwidth: 75-80nm
      "Viewing" angle: 15
      Switching time: 300 nanoseconds




Roithner Lasertechnik, model ELD-1300-515-1, price TBA
If you're into that really deep IR stuff, then you'll love this LED.
Emitting in the mid-IR at 1.3 microns, even my normally IR-sensitive Polaroid digital camera has problems picking this ordinary looking 5mm LED up. 1.3 microns (1,300nm) is normally thought of as a laser wavelength in the telecom and optical fiber industry. This is the only LED I'm aware of that emits in this range.


A look inside this elusive and one-of-a-kind mid-infrared LED.

The die is larger than usual, and it uses a perimeter contact bond instead of the traditional center ball or star bond. The rest of the LED looks quite ordinary, from the clear epoxy package to the leadframe & die cup.

These are the basic specs from the enclosed data sheet:
    Vf = 1 volt DC
    If = 50mA
    Radiant power = 2.3mW at 50mA (4.0mW at 100mA)
    Peak wavelength = 1.280 microns
    Spectral line halfwidth = 400nm
    "Viewing" angle = 15
This LED can take 100mA at absolute maximum, but then cooling will become an issue and device lifetime may be shortened. LED also has an unusually low tolerance for reverse voltage, with 1 volt being the absolute maximum allowable.
Chemistry is Indium Gallium Arsenide / Indium Phosphide QW
The light meter I normally use is totally insensitve to this wavelength. In fact, the reading actually went down when this LED was brought near its sensor. However it did weakly illuminate a photochemical type IR detection card.

Andreas at Roithner Lasertechnik graciously sent this sample along with samples of LEDs in two other bizarre IR wavelengths; these will be added to the page as time permits.


Roithner Lasertechnik, model ELD-740-524, price TBA
Cherry red Most scientists consider wavelengths much above 700nm to be in the infrared range; to be more precise, "near-IR". This is one such LED. Most people should still be able to see the LED glowing a very obvious, but fairly dim, deep red color, with its 740nm wavelength.

The LED puts out about 28mW, yet because it is all the way at the end of the visible spectrum, it appears much dimmer than even those cheap red LEDs you find in the VCR or the coffeemaker.

The viewing angle is fairly narrow; advertised as 24.

Starting around 720nm, many digital cameras begin to interpret deep red and NIR light as some other color, starting with a red-orange color, progressing through yellowish orange, yellow, and purplish white. As the wavelength increases (goes even deeper towards IR) the camera's pictures show this color shift, eventually ending up with a faint violet color that is occasionally seen at wavelengths near 1064nm if the optical power is high enough (such as with YAG lasers)

You will see this type of phenomenon happening with the next few LEDs, which are 780nm, 810nm and 905nm respectively.



Roithner Lasertechnik, model ELD-780-524, price TBA
Cherry red Here is an LED that approaches the limits of most people's vision. Emitting 28 milliwatts at 780nm, this appears to the eye to emit a very dull cherry red glow. Most people should still be able to see the LED glowing dimly, but some people may not.

This LED is also on the detection threshold of those photochemical IR sensor cards, and you really have to saturate the card with white or blue light first, or else the emission may be too weak to be visible within just few moments.

The viewing angle is fairly narrow; advertised as 24.

Incidentally, this LED is the same wavelength as the laser diodes used in compact disc players and older CD-ROM drives - the kind that can only read CD-ROM and audio discs, not newer ones like recordable CD or those which can play DVDs.

It is extremely rare to find an LED with this 780nm emission wavelength (especially with this high of a power output!); the 740nm wavelength in the previous sample is also rare to find in an LED.



Roithner Lasertechnik, model ELD-810-524, price TBA
Cherry red Now we're getting to true IR, which very few people can see. Emitting 28 milliwatts at 810nm, this appears to the eye to emit an almost imperceptible dull cherry red glow. Many people will no longer be able to see the output at this wavelength, but some can.

The output from this LED is easily detectable on IR detector cards and with most non-film cameras. As you can see, the camera "sees" this LED as a kind of purplish white color.

The viewing angle is fairly narrow; advertised as 24.





Roithner Lasertechnik, model ELD-905-524, price TBA
Invisible Finally, this 905nm IR LED is truly invisible to the eye; and can only be detected by such items as electronic photodetectors, digital cameras & camcorders, and photochemical IR detection cards, such as Radio Shack's 276-0099.
When pushed to its limits, this LED produces some output that is visible to the eye. Remember, LEDs aren't truly monochromatic, but instead emit over a small range. If the lower end of that range is within the limits of the human eye, sometimes a weak, dull red glow can be detected.

IR sensor cards illuminate brightly when exposed to this LED's light.

The emission angle (you can't see it, so viewing angle no longer makes sense) is fairly narrow; advertised as 24.





Roithner Lasertechnik, model SHPL-810-260, price TBA
big giant LED This is the evil twin to the SHPL-660 on the Red LED page. Mounted in a very beefy metal stud package, this LED means business.

With an optical output of 250 milliwatts at 810nm, this infrared powerhouse will fry your eyeballs if you stare into it.

This LED has an array of six series-connected AlGaAs chips inside.


Since this LED is so powerful it overloads my new photometer, I measured it using an equally new photometric grade photovoltaic cell provided by Don Klipstein. Using this type of photometer, the LED generated a current of almost 150mA in the cell, which works out to a staggering 240.7 milliwatts!
To put this in perspective, my "new" Techtronix J-16 Digital Photometer overloads with more than 2 milliwatts of light at any wavelength, even when the instrument is set at its highest range.

If this were a laser diode, it would have enough energy to burn paper & wood or use as a major league cigarette lighter if it were focused correctly. But since the active area is so large, you can barely perceive the thermal (heat) output with the top of a finger. And even then, it may just be an illusion.

Even so, DO NOT, and I mean DO NOT look directly into this LED from any closer than about three feet away.



The picture on the left was taken from 26" away, the one on the right from about 6" away from the target.


Spectrographic plot
Spectrographic analysis of this LED.


Spectrographic plot
Same as above; newer spectrometer software & settings used.
USB2000 spectrometer graciously donated by P.L.


(Update 12-05-07): From an email sent by www.led-eshop.de, comes this:
"This LED was made in St. Petersburg, Russia by our colleagues. Roithner Lasertechnik only distributes those LEDs, buying them from another intermediate seller- EPIGAP Optoelektronik GmbH from Berlin. The measurements and the data sheet for SHPL-810-260 (ELJ-810-xxx) was made earlier by me. Newer datasheets from EPIGAP Optoelektronik GmbH have sometimes mistakes because of lack of true specialists in the field at the company."



Original Gallium Arsenide infrared LED, circa. early to mid 1970s; internal structure suggest moderate age.

Two samples of IR LED arrived awhile back; however both of them are candidates for the Virtual LED Museum, and you will eventually find them there. But in case you don't have a lot of time to snoop around this fun little website or found the museum exhibit isn't complete yet, here they are for you.

insides of GaAs IR LED

This is an early Gallium Arsenide infrared LED model. Notice the very unusual dual-whisker construction. A pair of thin, probably platinum wires are attached to a solid gold bonding pad on the LED chip's jet-black surface.
The gold & platinum show up well in ordinary light, but this LED only photographs well in its own infrared emission, hence the funny colored image you see here; taken with a CCD camera sensitive to the invisible 0.94 micron (940 nanometer) emission wavelength.

This is the same type of chemistry used in the first commercially successful LED, and is made with the compound Gallium Arsenide; which is the metallic element gallium and the transitional element arsenic (familiar to some of you as an outdated type of mouse & rat poison - or as wife poison in Hitchcock style mystery programs). When the two elements were mixed correctly and crystallized in a special oven, the LED was born.

This LED needed just under 1.5 volts to operate, and 50mA of current was needed for it to function very well at all. Early examples of this LED began to surface right around or shortly after 1960. Most LEDs from this era were made in tiny little metal cans or in ceramic packages; the familiar "LED-shaped" plastic packages you see today really didn't begin to surface until around 1970.



Gallium Aluminum Arsenide (newer type) IR LED, pedigree of this sample is unknown)
Here is a more modern type of infrared (IR) LED.
This LED was made using a compound of Gallium Aluminum Arsenide (GaAlAs) and scientists found that adding aluminum increased the LED's emission greatly.

This LED is known as the High Efficiency infrared, and they usually come in several different wavelengths; the most common being 880nm and the least common being 940nm.
It too also needs around 50mA to work well, but it emits a much greater amount of infrared energy and thus, puts that 50mA to better use than the earlier type.

High efficiency IR
If you see in the photograph above, the die or chip inside resembles that of most all modern non-nitride LEDs - that is, a cube with a single wire attaching to a tiny ball in its center.
When the LED is operated at near full power, a dull cherry red glow is visible in a darkened room. This is because the LED emits a fairly broad spectrum of radiation, and some of it extends far enough towards the visible "rainbow" part of the spectrum that most people's eyes can detect it.

Radio Shack sells a couple of infrared LEDs using this chemistry. Look for their "high powered" IR LED in a slightly blue-tinted T1 3/4 case, and you will end up with one of these.

LEDs of this type are most commonly found in such items as TV remote controls, "people detectors" in some stores, IR beam communications devices, and some types of IR illuminators for night vision cameras. I have found that Lazer Tag guns use the older GaAs type for some reason, rather than these much 'brighter' GaAlAs LEDs.






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