LiDAR Optical Coating Technology: Applications from Laser Emitter to Receiving System

Introduction: The Relationship Between LiDAR and Coating Technology

LiDAR (Light Detection and Ranging) has become a core sensing technology in autonomous driving, drones, robotics, and industrial measurement. Its performance is directly influenced by the quality of the optical system design.
Key parameters — such as detection range, measurement accuracy, signal-to-noise ratio, and environmental adaptability — all depend on the optical characteristics of its components.

Among these components, optical coatings play a decisive role in ensuring high transmittance, high reflectivity, and long-term durability.

In a LiDAR system, three optical components are most critical in terms of coating performance:

• Laser Emitter Output Window
• Scanning Mechanism Mirror Surface (MEMS or Rotating Mirror)
• Receiver Optics (Lenses and Optical Filters)

This article provides a comprehensive analysis of LiDAR optical coating technologies, covering applications, industry challenges, process trends, and coating methods, and concludes with how SIMVACO’s advanced vacuum coating equipment supports these technologies in real-world production.

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I. Key Components and Coating Applications

1. Laser Emitter

The laser emitter is the light source of LiDAR. Its output window must maintain high transmission, low reflection, and excellent resistance to laser-induced damage.

Application Scenarios:

• Automotive LiDAR:
  In autonomous vehicles, the laser emitter window operates under high power and long durations. It must maintain optical efficiency for 905 nm or 1550 nm lasers.
  The 1550 nm high-power laser, in particular, is favored for its eye safety (IEC 60825 standard) but requires coatings with a high laser damage threshold (LIDT ≥ 1–5 J/cm², as reported in IEEE optical materials studies).
• Industrial and Drone LiDAR:
  Requires high transmission and environmental resistance (dustproof, waterproof, and UV-resistant).

Coating Requirements & Techniques:

• Film Type: Anti-reflective (AR) + Protective Layer
• Recommended Processes: Ion-Assisted Deposition (IAD), Magnetron Sputtering, Ion Beam Sputtering (IBS);
  For 1550 nm systems: add DLC or PECVD protective coatings.
• Key Metrics: Transmittance ≥ 97–99%, Reflectance ≤ 0.5%, High power endurance.

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2. Scanning Mechanism (MEMS Micromirrors / Rotating Mirrors)

The scanning system directs the laser beam across the field of view, and the mirror coating directly affects reflectivity, durability, and stability.

Application Scenarios:

• MEMS LiDAR:
  Compact and cost-effective for mass-market automotive applications. The coating must be lightweight, uniform, and low-stress (<50 MPa) to maintain mirror precision.
• Rotating LiDAR:
  Used for panoramic scanning. The metal coating must endure high laser power and resist oxidation and contamination.

Coating Requirements & Techniques:

• Film Type: High Reflective (HR) + SiO₂ / Al₂O₃ Protective Layer
• Recommended Processes: PVD Metal Coating, Multi-Arc Ion Plating
• Key Metrics: Reflectivity ≥ 98–99%, High density, Oxidation and contamination resistance.

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3. Receiver Optics (Lens + Filter)

The receiver optics collect the reflected laser signal and filter out background noise to improve SNR.

Application Scenarios:

• Lenses: AR coatings enhance transmittance and signal strength.
• Optical Filters (Bandpass Filters):
  Precisely transmit laser wavelengths (905 nm / 1550 nm) while blocking sunlight and ambient light, critical for detection accuracy.

Coating Requirements & Techniques:

• Film Type: AR + Multilayer Narrow Bandpass Interference Coating
• Recommended Processes: Magnetron Sputtering or Ion Beam Sputtering (IBS)
• Key Metrics:

1. Transmittance ≥ 98–99%
2. Film uniformity ±1–2 nm
3. Center wavelength accuracy ±1–2 nm
4. Bandwidth ±5 nm
5. Durability per ASTM/ISO environmental standards (humidity, salt spray, abrasion).

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II. Industry Status and Technical Challenges

1. Precision and Uniformity Limitations
   For high-power 1550 nm LiDARs, traditional IAD or basic sputtering processes cannot achieve the ±2 nm accuracy required for optical interference coatings.
2. Durability and Environmental Adaptability
   In automotive environments, coatings are exposed to high temperature, humidity, and UV light, leading to degradation or delamination over time.
3. Cost vs. Throughput Trade-off
   Complex multilayer coatings require high automation and precision control. Traditional systems struggle to balance mass production and quality consistency.
4. Miniaturization of Solid-State LiDARs
   MEMS and OPA (Optical Phased Array) LiDARs demand extremely low-stress and highly uniform coatings, beyond the capability of older deposition systems.

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III. Future Development Trends

1. High-Precision Hybrid Coatings (Broadband / Narrowband)
   Future LiDARs may combine multiple laser wavelengths or modulation schemes, requiring coatings that balance broadband transparency and narrowband selectivity.
2. High-Power and Environmental Robustness
   Coatings must withstand higher LIDT values and offer dustproof, waterproof, and scratch-resistant performance for automotive and industrial LiDARs.
3. Solid-State and Miniaturized LiDAR Evolution
   Low-stress, highly uniform coatings with nanometer-level control will be critical for MEMS and OPA systems.
4. Intelligent, Automated Manufacturing
   Future coating systems will feature in-situ monitoring, automatic multi-step deposition, and real-time film correction, enabling high throughput and consistency.

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IV. Coating Process Summary

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V. SIMVACO Advanced Vacuum Coating Equipment Advantages

SIMVACO, a global leader in vacuum coating system manufacturing, delivers reliable coating solutions for LiDAR optical production with the following advantages:

• Multi-Process Compatibility:
  Supports IAD, Magnetron Sputtering, IBS, PECVD, and DLC — suitable for all LiDAR optical components.
• High Precision Control:
  Real-time film thickness monitoring with ±1% uniformity ensures accuracy for narrowband filters and AR coatings.
• Automation & Productivity:
  Multi-chamber, fully automated deposition enables high-volume production for automotive and industrial LiDARs.
• Durability & Stability:
  High-vacuum environments and ion-assisted deposition produce dense, oxidation-resistant films with excellent environmental stability.

SIMVACO’s advanced vacuum coating equipment provides robust, repeatable performance for LiDAR systems — empowering next-generation autonomous driving, drone mapping, and industrial sensing applications.

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Conclusion

As LiDAR technology continues to evolve, demands on optical coating precision, uniformity, durability, and environmental resistance are becoming increasingly stringent.
From laser emitter windows to scanning mirrors and receiver optics, coating quality directly determines system performance and longevity.

Through scientifically designed coating structures and high-end vacuum deposition systems, LiDAR optical performance can be significantly enhanced.

SIMVACO’s advanced vacuum coating solutions are the ideal choice for LiDAR manufacturers — enabling reliable, high-precision optical coatings that meet the needs of the future intelligent sensing industry.

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📩 Contact SIMVACO

For more information on LiDAR optical coating equipment or custom vacuum coating solutions, please contact:

📞 WhatsApp / Phone: +86-15958205967
📧 Email: simon@simvaco.com
🌐 Website: https://simvaco.com

SIMVACO — Precision in Every Layer.