1
h
henry; hecto-; hour; Planck constant
2
HALO
high-altitude large optics
4
HB-LED
high-brightness LED
5
HBS
holographic beam sampler
7
HCCD
high-performance CCD
8
HCG
high-index-contrast subwavelength grating
9
HCMM
heat capacity mapping mission
13
HDA
head-disc assembly
14
HDSL
high-bit-rate digital subscriber loop
15
HDTV
high-definition TV
16
HDVS
high-definition video systems
17
HDWDM
high-density wavelength division multiplex
18
HEA
high-efficiency antireflection
19
HEAO
high-energy astronomy observatory
20
HEBS
high energy beam sensitive
22
HEM
hybrid electromagnetic wave; heat exchange method
23
HEMT
high-electron-mobility transistor
24
HEPA
high-efficiency particulate air
25
HEX
heat exchanger unit
27
HFS
hyperfine structure
28
HID
high-intensity discharge
29
HIP
hot isostatic pressing
30
HIPPI
high-performance parallel interface
31
HIRF
high-intensity radio frequency
33
HMD
head-mounted display; helmet-mounted display
34
HMFG
heavy metal fluoride glass
35
HMS
helmet-mounted sight
36
hn
energy of a quantum of radiation
37
HNDT
holographic nondestructive testing
38
HNIL
high-noise-immunity logic
39
HOE
holographic optical element