Laser diode collimator, large aperture, M9 x 0.5, high efficiency

Q: Glass optics vs. acrylic optics – when which?

Acrylic optics (PMMA plastic): low cost, light, dimensionally stable. Optically very good in standard applications, but temperature-sensitive – the refractive index changes with temperature, shifting the focus when variation exceeds ±5 °C. Perfectly adequate for indoor applications with stable conditions. Glass optics: heavier, more expensive, but temperature-stable. The refractive index stays nearly constant across wide temperature swings. Ideal for: outdoor mounting, unheated halls, machines with large temperature swings (welding, sawmills in summer/winter) and applications needing high repeat accuracy over long periods. Glass optics are available as an optional upgrade on our KLM and LLM modules.

Q: Dielectric mirrors vs. metallic mirrors – what are the differences?

Metallic mirrors (aluminium, silver, gold): reflection via a thin metal coating. Typically up to&gt;98 % reflectivity in the visible range. Benefits: broadband (from UV to IR), low cost. Drawbacks: lower power handling, prone to oxidation (especially silver), reflectivity depends on angle of incidence. Dielectric mirrors: reflection via multi-layer glass coatings that reflect through interference. Typically &gt; 99 % reflectivity in the optimized spectral range. Benefits: extremely high reflectivity, high power handling, no oxidation. Drawbacks: narrowband (optimized for a specific wavelength), more expensive. Our LS 50 is a dielectric mirror with &gt; 96–98 % reflectivity in the 400–700 nm range.

Q: What is the aperture of an optic?

The aperture is the usable opening diameter of an optic – the area through which light can enter the lens. Measured in millimetres. A larger aperture collects more light from the source – particularly important for laser diodes with a large emitter (e.g. Nichia NDG7575). Our Colli-LA collimator has a 5 mm aperture, gathering significantly more light than typical 3 mm collimators. Practical effect: brighter, more uniform output beam and less light lost at the diode edge. Related metric: the numerical aperture (NA) describes the ratio of aperture to focal length – and therefore the optic's acceptance angle.

Q: What does the focal length of a lens mean?

The focal length is the distance from the principal plane of a lens to the focal point, where parallel incoming light rays intersect. It is measured in millimetres (e.g. f = 4 mm on our Colli-LA). For collimators the focal length determines at which distance from the laser diode the lens must be mounted to collimate the beam – ideally the diode emits from the focal plane. Shorter focal lengths (3–4 mm): high aperture, good light gathering, compact – ideal for 12 mm modules. Longer focal lengths (8–20 mm): smaller aperture, less light gathering, but a narrower collimated beam – for long-distance applications.

Q: What is an AR coating (anti-reflective)?

An AR coating (anti-reflective coating) is a thin, multilayer coating on optical glass surfaces that reduces reflection and increases transmission. At an uncoated glass–air interface typically 4–8 % of the light is lost to reflection. A modern AR coating reduces this to &lt; 0.5 % per interface. For a lens with two interfaces that means 92 % transmission uncoated vs. &gt; 99 % coated. Benefits: higher optical efficiency, less stray light, lower back-reflection load on the laser diode. AR coatings are wavelength-specific – a coating for 532 nm behaves differently at 650 nm. Always check the spectral range of the optic.

Q: What is a collimator and what does it do?

A collimator is an optical lens or lens system that converts a divergent light beam into a parallel beam. Essential with laser diodes: the bare diode emits a strongly fanned-out beam; the collimator turns it into a bundled, parallel beam. Construction: usually an aspheric glass lens in an M9 × 0.5 or M12 threaded housing. High-quality collimators feature an AR coating (anti-reflective) for minimal light loss at the interfaces. Key parameters: focal length (typ. 3–6 mm), aperture (typ. 4–8 mm) and the AR coating's spectral range (e.g. 420–680 nm for visible light). Glass collimators are more temperature-stable than cheaper acrylic lenses.

Q: Which well-known manufacturers of laser diodes exist?

The leading manufacturers of industrial laser diodes: Nichia (Japan) – market leader for green and blue laser diodes, highest efficiency and service life; well-known models include the NDG7575 (1 W green, 520 nm) and the NUBM series (blue). Sharp (Japan) – strong second source for visible wavelengths; models such as GH05C01B9G (1 W green). Osram Opto Semiconductors (Germany) – broad portfolio from 405 to 850 nm. Sony – mainly for display and show applications. Ushio – industrial high-power diodes. For red and infrared the choice is wider; for green and blue Nichia and Sharp are the dominant sources.

Q: How does beam shaping (collimation) of a laser diode work?

A bare laser diode emits a strongly divergent, elliptical beam – the bare diode does not produce a usable spot but rather a fanned-out cone. For practical use the beam must be collimated – reshaped into a parallel, directed beam. Standard solution: a collimator lens directly in front of the diode, mounted in an M9 × 0.5 housing (brass or aluminium). A single-lens optic turns the divergent beam into an approximately parallel beam. On high-quality collimators (e.g. our Colli-LA) we use an aspheric glass lens with AR coating, 5 mm aperture, focal length approx. 4 mm. For especially round beam profiles, correction optics can be added behind the collimator.

Q: Why does a laser diode need a heat sink?

Laser diodes dissipate typically 50–70 % of the electrical power as heat – only a fraction becomes light. A 1 W laser diode therefore generates 1.5–2 W of waste heat in the semiconductor chip. Without a heat sink the junction temperature climbs to critical levels within seconds and the diode fails thermally. Consequences: drastic wavelength shift (red-shifted), efficiency collapse, irreversible destruction. Rule of thumb: every additional 10 °C in junction temperature roughly halves the service life. Practice: mount the diode in a massive metal holder (brass or aluminium), the holder on a heat sink with thermal compound, and add a fan or thermal convection for &gt; 1 W.

Q: What is a constant-current driver for laser diodes?

A constant-current driver is an electronic circuit that regulates the current flowing through a laser diode to an exact value – independent of input voltage and temperature variations. This is necessary because a laser diode's optical output depends linearly on current, not on voltage. A simple voltage supply would, with small temperature or supply fluctuations, lead to large current and therefore optical-output swings – in the worst case destroying the diode. Good drivers offer: constant-current regulation, soft-start, over-temperature protection, ESD protection and often analog/TTL modulation for pulsed operation. Matching drivers are available in our „Laser drivers“ category.

Colli-LA: Short-focal-length laser diode collimator (M9 × 0.5) with a large aperture of approximately 5 mm for very high efficiency. AR 420–680 nm.

€19.64

Delivery time: In stock

Product number: Colli-LA

Laser diode collimator, large aperture, M9 x 0.5, high efficiency

Colli-LA M9 Collimator, Large Aperture: Short-focal-length glass collimator (focal length approx. 4.05 mm, aperture approx. 5 mm): The lens is positioned very close to the laser diode, resulting in exceptionally high transmission efficiency. Brass housing, AR coating 420–680 nm.

Large aperture approx. 5 mm, focal length approx. 4.05 mm
Very high transmission efficiency
M9 × 0.5 thread, single glass lens, AR 420–680 nm

Technical Specifications:

External thread:	M9 x 0.5
Material:	Brass
Single-lens element:	made of glass
AR coating:	420–680 nm
Focal length:	approx. 4.05 mm
Total aperture:	approx. 5 mm

Glass optics vs. acrylic optics – when which?

Acrylic optics (PMMA plastic): low cost, light, dimensionally stable. Optically very good in standard applications, but temperature-sensitive – the refractive index changes with temperature, shifting the focus when variation exceeds ±5 °C. Perfectly adequate for indoor applications with stable conditions. Glass optics: heavier, more expensive, but temperature-stable. The refractive index stays nearly constant across wide temperature swings. Ideal for: outdoor mounting, unheated halls, machines with large temperature swings (welding, sawmills in summer/winter) and applications needing high repeat accuracy over long periods. Glass optics are available as an optional upgrade on our KLM and LLM modules.

Dielectric mirrors vs. metallic mirrors – what are the differences?

Metallic mirrors (aluminium, silver, gold): reflection via a thin metal coating. Typically up to>98 % reflectivity in the visible range. Benefits: broadband (from UV to IR), low cost. Drawbacks: lower power handling, prone to oxidation (especially silver), reflectivity depends on angle of incidence. Dielectric mirrors: reflection via multi-layer glass coatings that reflect through interference. Typically > 99 % reflectivity in the optimized spectral range. Benefits: extremely high reflectivity, high power handling, no oxidation. Drawbacks: narrowband (optimized for a specific wavelength), more expensive. Our LS 50 is a dielectric mirror with > 96–98 % reflectivity in the 400–700 nm range.

What is the aperture of an optic?

The aperture is the usable opening diameter of an optic – the area through which light can enter the lens. Measured in millimetres. A larger aperture collects more light from the source – particularly important for laser diodes with a large emitter (e.g. Nichia NDG7575). Our Colli-LA collimator has a 5 mm aperture, gathering significantly more light than typical 3 mm collimators. Practical effect: brighter, more uniform output beam and less light lost at the diode edge. Related metric: the numerical aperture (NA) describes the ratio of aperture to focal length – and therefore the optic's acceptance angle.

What does the focal length of a lens mean?

The focal length is the distance from the principal plane of a lens to the focal point, where parallel incoming light rays intersect. It is measured in millimetres (e.g. f = 4 mm on our Colli-LA). For collimators the focal length determines at which distance from the laser diode the lens must be mounted to collimate the beam – ideally the diode emits from the focal plane. Shorter focal lengths (3–4 mm): high aperture, good light gathering, compact – ideal for 12 mm modules. Longer focal lengths (8–20 mm): smaller aperture, less light gathering, but a narrower collimated beam – for long-distance applications.

What is an AR coating (anti-reflective)?

An AR coating (anti-reflective coating) is a thin, multilayer coating on optical glass surfaces that reduces reflection and increases transmission. At an uncoated glass–air interface typically 4–8 % of the light is lost to reflection. A modern AR coating reduces this to < 0.5 % per interface. For a lens with two interfaces that means 92 % transmission uncoated vs. > 99 % coated. Benefits: higher optical efficiency, less stray light, lower back-reflection load on the laser diode. AR coatings are wavelength-specific – a coating for 532 nm behaves differently at 650 nm. Always check the spectral range of the optic.

What is a collimator and what does it do?

A collimator is an optical lens or lens system that converts a divergent light beam into a parallel beam. Essential with laser diodes: the bare diode emits a strongly fanned-out beam; the collimator turns it into a bundled, parallel beam. Construction: usually an aspheric glass lens in an M9 × 0.5 or M12 threaded housing. High-quality collimators feature an AR coating (anti-reflective) for minimal light loss at the interfaces. Key parameters: focal length (typ. 3–6 mm), aperture (typ. 4–8 mm) and the AR coating's spectral range (e.g. 420–680 nm for visible light). Glass collimators are more temperature-stable than cheaper acrylic lenses.

Which well-known manufacturers of laser diodes exist?

The leading manufacturers of industrial laser diodes: Nichia (Japan) – market leader for green and blue laser diodes, highest efficiency and service life; well-known models include the NDG7575 (1 W green, 520 nm) and the NUBM series (blue). Sharp (Japan) – strong second source for visible wavelengths; models such as GH05C01B9G (1 W green). Osram Opto Semiconductors (Germany) – broad portfolio from 405 to 850 nm. Sony – mainly for display and show applications. Ushio – industrial high-power diodes. For red and infrared the choice is wider; for green and blue Nichia and Sharp are the dominant sources.

How does beam shaping (collimation) of a laser diode work?

A bare laser diode emits a strongly divergent, elliptical beam – the bare diode does not produce a usable spot but rather a fanned-out cone. For practical use the beam must be collimated – reshaped into a parallel, directed beam. Standard solution: a collimator lens directly in front of the diode, mounted in an M9 × 0.5 housing (brass or aluminium). A single-lens optic turns the divergent beam into an approximately parallel beam. On high-quality collimators (e.g. our Colli-LA) we use an aspheric glass lens with AR coating, 5 mm aperture, focal length approx. 4 mm. For especially round beam profiles, correction optics can be added behind the collimator.

Why does a laser diode need a heat sink?

Laser diodes dissipate typically 50–70 % of the electrical power as heat – only a fraction becomes light. A 1 W laser diode therefore generates 1.5–2 W of waste heat in the semiconductor chip. Without a heat sink the junction temperature climbs to critical levels within seconds and the diode fails thermally. Consequences: drastic wavelength shift (red-shifted), efficiency collapse, irreversible destruction. Rule of thumb: every additional 10 °C in junction temperature roughly halves the service life. Practice: mount the diode in a massive metal holder (brass or aluminium), the holder on a heat sink with thermal compound, and add a fan or thermal convection for > 1 W.

What is a constant-current driver for laser diodes?

A constant-current driver is an electronic circuit that regulates the current flowing through a laser diode to an exact value – independent of input voltage and temperature variations. This is necessary because a laser diode's optical output depends linearly on current, not on voltage. A simple voltage supply would, with small temperature or supply fluctuations, lead to large current and therefore optical-output swings – in the worst case destroying the diode. Good drivers offer: constant-current regulation, soft-start, over-temperature protection, ESD protection and often analog/TTL modulation for pulsed operation. Matching drivers are available in our „Laser drivers“ category.

How is a bare laser diode driven correctly?

A bare laser diode needs a constant-current driver – not a simple voltage supply. Reason: the diode has a very steep current/light-output curve. Even 5 % current variation can destroy the diode. Concrete requirements: 1. Constant-current-regulated supply at the operating current specified in the datasheet (e.g. 1.6 A for Nichia NDG7575). 2. Soft-start (no abrupt current jump). 3. Protection against voltage spikes on the supply side. 4. Adequate heat dissipation via a heat sink (typically < 30 °C junction temperature). 5. ESD protection during handling – bare diodes are extremely ESD-sensitive.

What is a TO-9 laser diode?

TO-9 is a standardized package format for laser diodes – a cylindrical metal can with 9 mm diameter. The package contains the laser semiconductor chip, a protective cap with exit window and the electrical pins (typically 3). Benefits: uniform mechanical interface, good heat dissipation through the metal housing, easy integration into sockets and heat sinks. TO-9 is, alongside TO-5 (5.6 mm) and TO-18 (5.6 mm, older), the most common package for high-power laser diodes with > 200 mW. Examples: Nichia NDG7575 (1 W green), Sharp GH05C01B9G (1 W green). A bare TO-9 diode is a pure component without collimator and without driver.