Relative Partial Dispersions
N-BK7(H-K9L)				N-F2(H-F4)
Ps,t	0.3071	P's,t	0.3049	Ps,t	0.2379	P's,t	0.2346
PC,s	0.5588	P'C',s	0.6038	PC,s	0.4919	P'C',s	0.5305
Pd,C	0.3073	P'd,C'	0.2562	Pd,C	0.2934	P'd,C'	0.2439
Pe,d	0.2386	P'e,d	0.2370	Pe,d	0.2366	P'e,d	0.2334
Pg,F	0.5359	P'g,F'	0.4761	Pg,F	0.5885	P'g,F'	0.5211
Pi,h	0.7499	P'i,h	0.7447	Pi,h	0.9570	P'i,h	0.9438

Abnormal  Dispersions
N-BK7(H-K9L)				N-F2(H-F4)
△PC,t	0.0171	△PC,s	0.0052	△PC,t	0.0122	△PC,s	0.0042
△PF,e	-0.0006	△Pg,F	-0.0005	△PF,e	0.0002	△Pg,F	0.0047

How are materials selected for triplet achromatic lenses?
The choice of material for triplet achromatic lenses is critical and directly affects chromatic aberration correction and optical performance. The following are the main considerations and selection methods:
1. Dispersion characteristics
Abbe number: choose a material with a large difference in Abbe number, usually one piece of low dispersion material (corona glass, high Abbe number) and the other piece of high dispersion material (flint glass, low Abbe number) to effectively correct for color differences.
2. Refractive index
Refractive index matching: selection of materials with different refractive indices to help correct spherical aberration and other aberrations. Typically, a high index material is used for positive lenses and a low index material is used for negative lenses.
3. Optical properties
Transmittance: the material should have high transmittance in the working band to minimize light loss.
Homogeneity: the material should be optically homogeneous to avoid affecting the imaging quality.
4. Mechanical and thermal properties
Mechanical strength: the material should have sufficient mechanical strength to withstand the stresses of processing and use.
Thermal stability: the coefficient of thermal expansion and thermal stability of the material should be suitable for the working environment to avoid temperature changes affecting the performance.
5. Cost and availability
Cost: select materials that cost less while meeting performance requirements.
Availability: materials should be easily accessible to ensure sustainability in production and maintenance.
6. Processing performance
Processing difficulty: the material should be easy to process and polish to ensure the surface accuracy and finish of the lens.

Highly Recommended Optical Lenses from Yutai Optics:
BK7 Lenses
Optical Triplet Lenses
Optical Doublet Lenses
N-BAF10 / N-SF57 Achromatic Lenses