Next-generation acne treatment plan | 1726nm laser therapy

In recent years, optical technology applications in medical aesthetics have expanded continuously. As a new safe method for acne treatment, it has been widely used. Multiple wavelength bands can effectively treat acne but also have limitations:

1) Blue and green light — Effects vary among individuals

In the visible light spectrum, blue and green light can oxidize photosensitive porphyrins produced by Propionibacterium acnes, killing bacteria and reducing inflammation. However, effects vary among individuals; some patients develop bacterial resistance leading to reduced efficacy. Blue light has insufficient penetration depth and is only effective for mild to moderate inflammatory acne. During green light trials, acne rebound was observed.

2) Red light — Cannot completely eradicate

Red light has relatively good penetration but still cannot completely suppress deep inflammation.

3) Short-wave infrared — Requires local anesthesia or cooling system

Short-wave infrared (SWIR) lasers have stronger penetration, reaching deep into sebaceous glands and hair follicles. Using the photothermal effect of the laser, they directly destroy sebaceous glands and intracellular Propionibacterium acnes, providing better long-term effects. Clinical trials of 1064nm and 1540nm lasers have shown certain efficacy, but require local anesthetics or cooling systems; otherwise, patients endure severe pain, persistent facial erythema, and even direct epidermal damage.

4) Photodynamic therapy (PDT) — Burning, stinging, requires light avoidance

PDT involves applying photosensitizing drugs (such as ALA) to lesions and irradiating with specific wavelengths to activate the photosensitizer to produce reactive oxygen species, damaging or killing diseased cells. PDT is effective for stubborn acne, but activation of the photosensitizer may cause burning and stinging sensations, and patients must avoid light for a period due to residual photosensitizer.

Efficient, safe, durable, painless treatment plan:

1726nm laser treatment

To further simplify treatment, avoid pain risks, and reduce patient burden, the industry seeks a treatment that does not require photosensitizers and directly targets sebaceous glands rather than other tissues. The 1726nm wavelength laser has been proven to selectively deliver light energy to specific chromophores within sebaceous glands, where absorption is much higher than water. Short, high-power pulses can precisely destroy sebaceous gland structures while minimizing thermal damage to surrounding tissues. The 1726nm wavelength can penetrate up to 1.5mm beneath the skin, directly targeting deep sebaceous glands to reduce acne at its source.

Figure 1 Absorption coefficients of water and sebum in the infrared band ^[1]

Numerical simulations and in vivo experiments confirm that under controlled pulse energy and duration, this wavelength laser can locally raise sebaceous gland temperature above 60°C, causing irreversible gland damage and directly inhibiting excessive sebum secretion. Meanwhile, epidermal temperature remains below 42°C, further protecting the epidermis and reducing treatment discomfort and side effects such as postoperative erythema and edema, ensuring safety.

Figure 2 Skin histology images: no obvious epidermal damage (A), complete (B) and partial (C) thermal damage to sebaceous glands, (D) undamaged sebaceous gland. ^[2]

Multiple clinical studies show that 1726nm laser is effective for mild, moderate, and severe acne, reducing inflammatory lesions by 50% after three treatments, with effects maintained during 24-month long-term follow-up as shown in Figure 3. Additionally, 1726nm laser shows consistent efficacy and safety across different skin types (including darker skin tones), with only transient erythema or edema post-treatment, no serious adverse reactions, and good patient tolerance. The 1726nm laser, through its unique photothermal mechanism selectively targeting sebaceous glands, offers an efficient, safe, and durable solution for acne treatment. Its remarkable targeting ability, broad skin compatibility, minimal side effects, and high patient satisfaction make it a pioneer in acne treatment and demonstrate significant competitiveness in the medical aesthetics field.

Figure 3 Clinical photos of a 24-year-old female subject at baseline pre-treatment (A) and at 6 (B), 21 (C), and 35 (D) months after the fourth treatment follow-up. ^[2]

Changguang Huaxin uses independently developed high-power indium phosphide chips combined with self-developed module automated assembly equipment based on Active Alignment (AA) technology to launch a 1726nm wavelength locked fiber-coupled laser with a 365μm fiber core diameter for the medical aesthetics industry, continuously outputting over 100W. , Figure 4 shows the power curve at a cooling temperature of 25℃, with the laser electro-optical conversion efficiency exceeding 20%.

Figure 4 Continuous output power curve of 1726nm wavelength locked fiber-coupled laser

This product locks the wavelength at 1726±1.5nm, with a spectral width (FWHM) <1.5nm. It can achieve wavelength locking immediately upon startup and maintain wavelength locking from threshold current to operating current range. Figure 5 (A) shows the locking effect at different currents during continuous operation, with a cooling temperature of 25℃. The product can achieve wavelength locking over a temperature range of 10-40℃. Figure 5 (B) shows the locking effect when continuously powered at 16A while changing the cooling temperature. The product's wavelength drift coefficient is 0.012nm/℃, significantly better than similar products.

Figure 5 Wavelength locking effect of 1726nm laser under continuous output with varying current (A) and varying temperature (B)

This product can also achieve wavelength locking in pulse operation mode. Figure 6 shows the wavelength locking effects at a cooling temperature of 25℃ with duty cycles of 70% (pulse width 35ms), 50% (pulse width 25ms), 30% (pulse width 15ms), and 10% (pulse width 10ms).

Figure 6 Wavelength locking effect of 1726nm laser under different duty cycle conditions

Changguang Huaxin

Changguang Huaxin is dedicated to the research and production of semiconductor laser chips. Its core technology covers the most critical areas of the semiconductor laser industry, overcoming long-standing technical challenges in epitaxial growth, cavity surface treatment, packaging, and fiber coupling. It has established a fully independent and controllable complete process platform and mass production line from chip design, MOCVD (epitaxy), FAB wafer fabrication, cleaving/coating, packaging, testing, optical coupling, to direct semiconductor lasers. It owns three major production lines of 2-inch, 3-inch, and 6-inch wafers, with two main product structures: edge-emitting EEL and surface-emitting VCSEL, and three major material systems: GaAs (Gallium Arsenide), InP (Indium Phosphide), and GaN (Gallium Nitride). It is one of the few IDM semiconductor laser companies worldwide with key process production capabilities such as 6-inch line epitaxy and wafer manufacturing.

References:

[1] Matteo G.S., Amogh K., Michael K., A novel 1726-nm laser system for safe and effective treatment of acne vulgaris. Lasers in Medical Science (2022) 37:3639–3647.

[2] Emil A.T, Rafael S, Michael E et al, Treatment of Acne With a 1726 nm Laser, Air Cooling, and Real-Time Temperature Monitoring, Software-Assisted Power Adjustment to Achieve a Temperature Endpoint With Selective Sebaceous Gland Photothermolysis. Lasers in Surgery and Medicine (2025):1-16.