What is the difference between monocrystalline and polycrystalline silicon?
Monocrystalline silicon: structurally ordered, excellent performance, suitable for high-end applications, but high cost.
Polycrystalline silicon: structured polycrystalline, slightly inferior performance, suitable for cost-sensitive applications.

Yutai's Standard list of Silicon PCX Lens
No.	Material	Diameter(mm)	FL（mm)
YT02	Silicon	6.65	5.49
YT03	Silicon	6.65	3.89
YT06	Silicon	7.6	7.01
YT08	Silicon	8	11.07
YT17	Silicon	22	44.21
YT129	Silicon	16	18.5
YT134	Silicon	14.5	23.89
YT156	Silicon	3	1.77
YT159	Silicon	5	1.85
YT170	Silicon	5.2	2.78
YT203	Silicon	6.9	5.47

What coating is Yutai's silicon lens generally coated?
Yutai's silicon lenses can be coated with AR, BBAR and DLC coating.


Highly Recommended Silicon from Yutai Optics:
IR Silicon
Optical Plano Silicon Windows
Optical Aspheric Silicon Lenses
Silicon Right Angle Prisms
Silicon IR Longpass Filters
Silicon Blanks