set title "wavelength / voltage " 
set xlabel "voltage[V]" 
set ylabel "measured wavelength / voltage[m/V]" 
set format y "%.2tE%+03T" 
plot [2800:5200] '-' using 1:2:3 title "d_1" with yerrorbars, \ 
'-' using 1:2:3 title "d_2" with yerrorbars,\ 
1.22632E-09 title "theoritical value" 
3000    1.24293E-09    5.23929E-11    2.34947E-11 
3500    1.28436E-09    5.30092E-11    2.34947E-11 
4000    1.31086E-09    5.33437E-11    2.34947E-11 
4500    1.29146E-09    5.20411E-11    2.34947E-11 
5000    1.26284E-09    5.05305E-11    2.34947E-11 
EOF 
3000    1.29557E-09    5.4612E-11    1.24123E-10 
3500    1.30982E-09    5.40601E-11    1.24123E-10 
4000    1.35837E-09    5.52769E-11    1.24123E-10 
4500    1.36778E-09    5.51165E-11    1.24123E-10 
5000    1.03031E-09    4.12262E-11    1.24123E-10 
EOF