MOOR INSTRUMENTS moorLDI2 RESEARCH USER MANUAL
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1.2.2 LASER SAFETY moorLDI2-IR AND moorLDI2-HIR
There are two laser light sources within the moorLDI2-IR scanner. These are a visible red laser
diode, wavelength 660nm (the aiming or target beam) and the near infra-red laser diode, wavelength
785nm, used for the laser Doppler measurements. The lasers are housed in an optic combiner, each
laser has a collimating lens.
The combiner produces a single laser light output beam with the red and infra-red beams coaxial.
The visible aiming beam of 660nm has a power of less than 200µW and the infra-red working beam
has its accessible power between 2.0mW - 2.5mW (between 1.3mW – 1.5mW for the moorLDI2-
HIR).
The beam divergence is approximately 1.4milliradians.
The beam diameter (1/e
2
points) at 50cm from the Laser Aperture is approximately 1.2mm.
The nominal ocular hazard distance is 20 metres.
The scanner uses a 785nm infrared laser source with the accessible power set between 2.0mW -
2.5mW. This level of laser radiation is below the maximum permissible exposure (MPE) for skin
(which is approximately 28mW for laser radiation wavelength 785nm) but presents a significant
hazard if the eye is exposed to the full power of the laser beam, either by direct viewing along the
beam or by specular reflection. The 785nm infra-red beam is not visible to the human eye; however
this laser eye hazard is reduced because the visible aiming beam is always present. The aiming beam
enables the operator to see the position of the beam at all times.
The visible aiming beam is also sufficiently bright to provide blink reflex protection; however a
number of additional safety measures must be taken by the operator to minimise the risks
involved. These measures are described in the following sections.
1.2.2.1 Laser Protective Eyewear
WARNING - Eye protection should be used by patient and operator at all times in the measurement
area if the moorLDI2-IR imager is operated with the near infra-red laser ON. Eye protection for the
patient may be completely opaque (e.g. pads fixed over the eyes) if normal visibility is not required.
Eye protection for the operator(s) and patients:
Protective goggles or protective glasses must have an OD (optical density) of at least 1.5 for the
range 755nm to 855nm.
The protective eyewear for the operator must allow the LASER READY and IR EMISSION
indicators to be clearly seen (these indicators have a wavelength centred at approximately 585nm),
and the visible red (660nm) target beam to be clearly seen. All laser protective eyewear should be
clearly identified as being suitable for use with the moorLDI2-IR. Moor Instruments will normally
supply protective eye wear that can be worn over prescription glasses.
When, due to unusual operating requirements, the use of eye protection is not practicable, the
operator may use the moorLDI2-IR without eye protection. However this should only be undertaken
with the approval of the Laser Safety Officer.
If the patient’s or a volunteer’s face is to be scanned the patient or volunteer must use protective eye
wear.
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