LDI-4 Product Overview

The LDI-4 laser diode illuminator is a user inspired version of the original LDI-7.  Many researchers were asking for a laser launch that covered only the 4 basic lines: DAPI, FITC, TRITC, Cy5.  89 North listened and we responded.  The LDI-4 has only the lines you asked for.  While we reduced the number of lines inside the box, we made no compromises on the quality and performance you’ve come to expect from 89 North.  This unit is also available with a 488nm laser for FITC/GFP and with a 577nm laser for TRITC/mCherry…or both!

Have questions about the specifications or capabilities?  >> Ask an Engineer


Find specifications for our LDI-4 line of products below. Note that we can also work with you to provide solutions for your unique needs.

Source Type Laser Diodes
Lifetime 20,000 hrs – 2 year warranty
Laser Line (nm) 405 470 555 640
Continuous Wave Stability2 < 2% < 2% < 2% < 2%
Optical Power Min (mW)1 300 1000 1000 400
Max Rise Time1 < 10μs < 10μs < 2ms < 10μs
Max On/Off Frequency (Hz)3 > 1000 > 1000 100 > 1000
Output Options  optical fiber 4
Control Options TTL (>2.3 V)
Analog (0–5 V)
USB–DSP (virtual COM port) – SDK available upon request
Safety Interlocked housing
Safety interlock
Key interlock
IEC 60825 compliant
Dimensions 12.5” x 9.2” x 5.75”, 318mm x 234mm x 146mm
Weight ~9 lbs
Operating Temperature 15-30 ̊ C
Storage Temperature -18-50 ̊ C
Humidity < 80% non-condensing
Voltage 90–220 V AC, 50–60 Hz
Fuse None

1. Measured at 100% intensity, 23°C ± 2°C
2. Standard Deviation relative to the mean power measurements, measured at 100%
intensity, 23°C ± 2°C

3. Measured at 100% intensity, 50% duty cycle
4. Recommended output fiber is 400 μm, 0.39 NA bifurcated fiber



Find the unique features of our LDI-4 line up below.

High output power Shorter exposures
Faster imaging
Faster activation times in optogenetics and photoactivation experiments
Faster bleaching times in FRAP experiments
Feedback controlled optical stability Quantitative imaging, ideally suited for ratiometric imaging
More repeatable optogenetics experiments
Up to 100:1 linear dynamic range Ability to turn power down when needed and maintain stability and quantitative imaging
4 laser lines across the spectrum Covers most of the standard fluorescence probes
No user alignment Easy to use and maintain
TTL and Analog control No need for software specific drivers

Downloadable Documents

Please find links below to relevant downloads for our products.

LDI-4 Frequently Asked Questions (FAQs)

Here are answers to some of the most frequently asked questions we receive. Not seeing what you are looking for? >> Ask our engineers

The key factors to consider are: wavelength, power, delivery, repeatability, and cost. 89 North can deliver on all factors.

There are many differences but the four most important are:

  1. Small fiber size. The LDI is available in 100um, 400um, or larger fibers.

  2. Linearity. The LDI is an extremely useful light source for quantitative imagine, with linearity tracked internally from 1% to 100%.

  3. Specificity. The wavelengths of light from the LDI are not broad in spectrum line an LED. They are highly specific, which is critical for fluorescent illumination.

  4. Stability. The LDI is a very stable light source, which enables both accuracy any precision of light measurements.

Virtually none. The LDI ships fully aligned, and requires no regular alignment or cleaning.

Multi-mode lasers are the most economical lasers you can buy, on a photon/dollar basis. 89 North improves on this value further by providing light sources that are also quantitative and reliable. Pricing for varying models depending on their individual configuration. Click here to contact us to receive a quote.

Many factors, like wavelength, stability, and maintenance are critical issues that are often overlooked. Don’t just pay attention to cost, as all lasers are not the same.

Absolutely! The LDI is extremely stable, and linear from 1% to 100%.

The LDI is about the size of a small desktop computer. The dimensions are 12.5” x 9.2” x 5.75”, 318mm x 234mm x 146mm. You can find more specifications in the table at the top of the page.

The single most important thing to remember when setting up any laser light source is safety. Always review all documentation carefully, and consult your institution’s laser safety officer with any questions.

LDI-4 Peer Reviewed in Scientific Publications

Our light engines are used in some of the most pioneering labs across the world. Here are some of the scientific citations we’ve received.

Our Products are Used in the Nation's Most Advanced Labs

Our LDI products are used in some of the nation’s most advanced laboratories. Here are a few.

Request A Quote

Contact us for a free quote. Need something bespoke? We can work with you to configure a specialized range of laser lines and options.

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