Nyob rau hauv cov txheej txheem no, sib txawv wavelengths thiab outputs ntawm qis-theem teeb yog siv ncaj qha mus rau ib cheeb tsam. Lub cev nqaij daim tawv ces absorbs lub teeb. Lub teeb liab thiab ze-infrared ua rau cov tshuaj tiv thaiv, thiab cov hlwb puas teb nrog cov tshuaj tiv thaiv physiological uas txhawb nqa kev tsim dua tshiab.
Cov ntaub so ntswg yog feem ntau kho nrog wavelengths ntawm 600 thiab 700 nanometers (nm). Rau kev nkag mus tob dua, wavelengths ntawm 780 thiab 950 nm yog siv.
Txawm hais tias koj yuav hnov cov cuab yeej laser kov koj cov tawv nqaij, cov txheej txheem tsis mob thiab tsis muaj mob. Yuav tsis muaj suab nrov thiab koj yuav xav tias tsis muaj kev vibration lossis cua sov. Txhua qhov kev kho mob feem ntau siv sijhawm li ob peb feeb xwb.