Introduction:

OLPF, optical low pass filters, is made of several cemented layers of optical quartz material. An IR cut-off coating and anti-reflection coating are applied to the external surfaces. If the IR cut-off filter type is absorptive, the IR glass is inserted between the quartz layers. Clients' OLPF sizes and designs are also available. 

Single Crystal Quartz of this category is the most highly qualified optical quartz of the monohedron growth pyramid. It is used for optical low pass filters. It is also used for high power laser optics, precision polarizing optics, and optical fiber communications such as wave plates, polarization rotators and tuning elements are utilized in laser optics. For these applications, the most important parameters are inclusions and homogeneity.

We are special in leading manufacture of no striae crystal quartz.

BCT common synthetic crystal quartz Ingot Specifications:

• Size: Z<40mm, X<110mm, Y< 200mm
• Inclusions: better than IEC Ia grade
• Q-value: >2.40 million.
• Homogeneity: 5*10^-6
• No striae

Applications:

for customers who need higher optical quality quartz ingot or elements for

• OLPF
• Laser scope
• Communication

Specifications of quartz elements for OLPF

• Materials: As Ingot
• Degree: 45/0
• Size: 27.5*28.5, 36*72, 38*72
• Thickness: 0.56, 0.82, 0.91, 1.14, 1.27, 1.69

We can also meet special apertures demands.

Related technologies

OLPF is an optical element that can be used to improve the quality of imaging. It is placed in front of array optoelectronic imaging appliance such as CCD, CMOS, to remove the Interference from the beam above the spatial frequency of imaging device sampling into the imaging, as well as the interference from infrared rays into imaging. It is a necessary component of DSC, videophone, computer pick-up head, DVC, CCTV etc, which require high definition of imaging.

In high-quality digital imaging systems, optical low-pass filters (OLPF) are used to eliminate color Moire fringes. An OLPF cuts off the lens MTF above the sampling frequency of the imager resulting an overall MTF curve that approximates a step function in spatial domain.IR cut-off function is often incorporated into OLPF as well. See CCD/CMOS lens selection guide for discussion of OLPF and its impact on image quality. Download an application note on optical low-pass filters.

OLPF is made from optically high quality quartz coating with IR cut coating. Its optical characteristics are:

1．Surface Quality: ≤5 NR

2．Parallel: Double Parallelism≤0.01mm 

3．Axis Cutting Precision

4．Surface Smoothness

5．Spectrum Characteristics:

                            400nm         Tmin > 80% ；

                            420-620nm     Tmin > 85% ，Tave >90%；

                            650±10nm     T = 50% ；

                            700nm         T < 10% ；

                            720-1050nm    T < 3% ；

                            1100nm        T < 10%

Fig. OLPF spectrum characteristics