Laser Wireless Phone Charging: How It Works

Yes, laser wireless charging for phones is real and has been demonstrated in labs, but it is not yet a consumer product you can buy. The technology uses a focused infrared laser beam to deliver power over distances of several meters, and while it works, safety, efficiency, and regulatory hurdles remain before it reaches your pocket.

What Is Laser Charging?

Laser charging is a form of wireless power transfer that uses a narrow beam of light to carry energy from a transmitter to a receiver. Unlike traditional wireless charging pads that use electromagnetic induction and require the phone to sit on the pad, laser charging can send power across a room. The transmitter aims a laser at a photovoltaic cell on the back of the phone, which converts the light back into electrical current to charge the battery.

This is not science fiction. In 2018, a team at the University of Washington demonstrated a system that could deliver power to a device over a distance of 4.3 meters using a laser. More recently, companies like PowerLight Technologies have shown laser power delivery to drones and other equipment. However, these are research prototypes, not products you can order.

How Does Laser Charging Work?

The basic principle is simple: light carries energy, and a photovoltaic cell converts light into electricity. The transmitter contains a laser diode that emits infrared light. A lens or mirror focuses the beam, and a tracking system keeps the beam aimed at the receiver. The receiver is a small solar cell—often made of gallium arsenide, which is more efficient than standard silicon—that converts the laser light into direct current.

Key components in a laser charging system:

• Laser source: Usually an infrared laser diode, chosen for efficiency and safety.
• Beam steering: A motorized mirror or gimbal that tracks the phone’s position.
• Receiver: A photovoltaic cell with a lens to concentrate the light.
• Control electronics: Communication between transmitter and receiver to maintain alignment and adjust power.

The transmitter and receiver communicate via Bluetooth or a similar low-power link to coordinate aiming. When the phone moves, the transmitter adjusts the mirror to keep the beam on the receiver.

Safety and the Laser Hazard

The biggest concern with laser charging is safety. A laser beam powerful enough to charge a phone can also damage the human eye or skin. Infrared light is invisible, so you wouldn’t even see it coming. The University of Washington system used a laser with a power of about 2 watts, which is enough to cause eye damage if it hit someone directly.

To make it safe, researchers use several safeguards:

• Beam interruption detection: If something crosses the beam, the laser shuts off immediately.
• Low-power pilot beam: A weak visible laser is used to establish the path before the high-power beam is turned on.
• Receiver-only activation: The transmitter only sends power when it receives a specific signal from the phone, so it won’t fire randomly.

Even with these, regulatory agencies like the FDA in the US and similar bodies in other countries classify high-power lasers as hazardous. Consumer products would need to meet strict safety standards, which is a major hurdle.

Efficiency and Real-World Performance

Laser charging is not particularly efficient. The conversion chain—electricity to laser light, then light back to electricity—loses energy at each step. Typical end-to-end efficiency is around 10-20%, meaning most of the power from the wall is wasted as heat. For comparison, a good Qi wireless charging pad is about 70-80% efficient.

However, the advantage is distance. A Qi pad requires the phone to be within a few centimeters. Laser charging can work at several meters, and the efficiency doesn’t drop dramatically with distance as long as the beam stays focused. In the University of Washington test, the receiver got about 2 milliwatts of power—enough to run a small sensor, but far too little to charge a phone quickly. To charge a typical smartphone (which needs about 5-20 watts), you’d need a much more powerful laser, which raises safety concerns further.

Current Status and Companies

As of now, no major phone manufacturer offers laser charging in a retail product. However, several companies are working on the technology:

• PowerLight Technologies: Has demonstrated laser power delivery to drones and ground vehicles, and is working on longer-range systems.
• Wi-Charge: An Israeli company that uses infrared light (not exactly a laser, but similar) to charge devices over distances of several meters. They have shown prototypes for small devices like smart speakers and sensors.
• University research groups: Multiple universities continue to publish papers on laser power transfer, improving efficiency and safety.

These are all in the prototype or pilot stage. No consumer phone with a laser receiver is on the market.

Alternatives: RF and Ultrasonic Charging

Laser is not the only way to charge wirelessly over distance. Two other approaches are being explored:

• RF (radio frequency) charging: Uses radio waves like Wi-Fi to transmit power. Lower power, but can work through walls. Companies like Energous have demonstrated this for small devices.
• Ultrasonic charging: Uses sound waves to transfer energy. Can work through metal and water, but is less developed.

Each has trade-offs. RF is safer but delivers very low power. Ultrasonic is niche. Laser offers the best balance of power and range, but safety is the sticking point.

Frequently Asked Questions

Is laser charging dangerous to humans?

Yes, a high-power laser can cause eye or skin damage. That’s why any commercial system must include safety features like beam interruption and only activate when a receiver is detected. Research systems are designed with these safeguards, but consumer products are not yet available.

Can I buy a laser charger for my phone today?

No. No consumer laser charger is available for purchase. The technology is still in the lab or early prototype stage. You can only buy traditional wireless charging pads that require close contact.

How long would it take to charge a phone with a laser?

It depends on the laser power. A typical phone needs about 10-20 watts for fast charging. Current prototypes deliver only milliwatts, so charging would take many hours or days. To be practical, the laser power would need to be much higher, which increases safety risks.

Does laser charging work through walls or clothing?

No. A laser beam is line-of-sight. It cannot pass through walls, and even a piece of paper or clothing can block it. The receiver must be in direct view of the transmitter.

What is the maximum distance for laser charging?

Research demonstrations have achieved several meters—the University of Washington system worked at 4.3 meters. In theory, with a powerful enough laser and precise tracking, it could work over longer distances, but atmospheric absorption and beam spreading limit practical range.

Will laser charging replace traditional wireless charging?

Not in the near term. For now, it’s more likely to be used for specialized applications like charging sensors in hard-to-reach places or drones in flight. For everyday phone charging, the convenience of a pad is hard to beat, and the safety and efficiency issues of lasers remain unresolved.

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